Techniques to facilitate phase jump estimation for sidelink DMRS bundling

ABSTRACT

Apparatus, methods, and computer-readable media for facilitating phase jump estimation for SL DMRS bundling are disclosed herein. An example method includes receiving, from another device, first information at a first symbol of a first slot, the first slot including at least the first symbol and a first reference signal. The example method also includes receiving second information at a second symbol of a second slot, the second slot including at least the second symbol and a second reference signal, the first information and the second information being repetitions. The example method also includes generating a first reference signal copy based at least on the second reference signal and a phase jump between the first slot and the second slot. Additionally, the example method includes performing channel estimation across the first slot and the second slot based on an aggregation of the first reference signal and the first reference signal copy.

INTRODUCTION

The present disclosure relates generally to communication systems, andmore particularly, to sidelink communication.

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources. Examples of suchmultiple-access technologies include code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis 5G New Radio (NR). 5G NR is part of a continuous mobile broadbandevolution promulgated by Third Generation Partnership Project (3GPP) tomeet new requirements associated with latency, reliability, security,scalability (e.g., with Internet of Things (IoT)), and otherrequirements. 5G NR includes services associated with enhanced mobilebroadband (eMBB), massive machine type communications (mMTC), andultra-reliable low latency communications (URLLC). Some aspects of 5G NRmay be based on the 4G Long Term Evolution (LTE) standard. Some aspectsof wireless communication may comprise direct communication betweendevices based on sidelink. There exists a need for further improvementsin sidelink technology. These improvements may also be applicable toother multi-access technologies and the telecommunication standards thatemploy these technologies.

BRIEF SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In an aspect of the disclosure, a method of wireless communication at afirst wireless device is provided. The method may include receiving,from a second wireless device, first information at a first symbol of afirst slot, the first slot including at least the first symbol and afirst reference signal. The example method may also include receivingsecond information at a second symbol of a second slot, the second slotincluding at least the second symbol and a second reference signal, thefirst information and the second information being repetitions.Additionally, the example method may include generating a firstreference signal copy based at least on the second reference signal anda phase jump between the first slot and the second slot, the phase jumpbased on a first phase error associated with the first symbol and asecond phase error associated with the second symbol. The example methodmay also include performing channel estimation across the first slot andthe second slot based on an aggregation of the first reference signaland the first reference signal copy.

In another aspect of the disclosure, an apparatus for wirelesscommunication is provided. The apparatus may be a UE that includes amemory and at least one processor coupled to the memory, the memory andthe at least one processor configured to receive, from a second wirelessdevice, first information at a first symbol of a first slot, the firstslot including at least the first symbol and a first reference signal.The memory and the at least one processor may also be configured toreceive second information at a second symbol of a second slot, thesecond slot including at least the second symbol and a second referencesignal, the first information and the second information beingrepetitions. Additionally, the memory and the at least one processor maybe configured to generate a first reference signal copy based at leaston the second reference signal and a phase jump between the first slotand the second slot, the phase jump based on a first phase errorassociated with the first symbol and a second phase error associatedwith the second symbol. The memory and the at least one processor mayalso be configured to perform channel estimation across the first slotand the second slot based on an aggregation of the first referencesignal and the first reference signal copy.

In another aspect of the disclosure, an apparatus for wirelesscommunication at a UE is provided. The apparatus may include means forreceiving, from a second wireless device, first information at a firstsymbol of a first slot, the first slot including at least the firstsymbol and a first reference signal. The example apparatus may alsoinclude means for receiving second information at a second symbol of asecond slot, the second slot including at least the second symbol and asecond reference signal, the first information and the secondinformation being repetitions. Additionally, the example apparatus mayinclude means for generating a first reference signal copy based atleast on the second reference signal and a phase jump between the firstslot and the second slot, the phase jump based on a first phase errorassociated with the first symbol and a second phase error associatedwith the second symbol. The example apparatus may also include means forperforming channel estimation across the first slot and the second slotbased on an aggregation of the first reference signal and the firstreference signal copy.

In another aspect of the disclosure, a non-transitory computer-readablestorage medium storing computer executable code for wirelesscommunication at a UE is provided. The code, when executed, may cause aprocessor to receive, from a second wireless device, first informationat a first symbol of a first slot, the first slot including at least thefirst symbol and a first reference signal. The example code, whenexecuted, may also cause the processor to receive second information ata second symbol of a second slot, the second slot including at least thesecond symbol and a second reference signal, the first information andthe second information being repetitions. Additionally, the examplecode, when executed, may cause the processor to generate a firstreference signal copy based at least on the second reference signal anda phase jump between the first slot and the second slot, the phase jumpbased on a first phase error associated with the first symbol and asecond phase error associated with the second symbol. The example code,when executed, may also cause the processor to perform channelestimation across the first slot and the second slot based on anaggregation of the first reference signal and the first reference signalcopy.

In an aspect of the disclosure, a method of wireless communication, witha first wireless device, at a second wireless device is provided. Themethod may include transmitting, to the first wireless device, firstinformation at a first symbol of a first slot, the first slot includingat least the first symbol and a first reference signal. The examplemethod may also include transmitting second information at a secondsymbol of a second slot, the second slot including at least the secondsymbol and a second reference signal, the first information and thesecond information being repetitions.

In another aspect of the disclosure, an apparatus for wirelesscommunication, with a first wireless device, at a second wireless deviceis provided. The apparatus may be a UE that includes a memory and atleast one processor coupled to the memory, the memory and the at leastone processor configured to transmit, to the first wireless device,first information at a first symbol of a first slot, the first slotincluding at least the first symbol and a first reference signal. Thememory and the at least one processor may also be configured to transmitsecond information at a second symbol of a second slot, the second slotincluding at least the second symbol and a second reference signal, thefirst information and the second information being repetitions.

In another aspect of the disclosure, an apparatus for wirelesscommunication, with a first wireless device, at a second wireless deviceis provided. The apparatus may include means for transmitting, to thefirst wireless device, first information at a first symbol of a firstslot, the first slot including at least the first symbol and a firstreference signal. The example apparatus may also include means fortransmitting second information at a second symbol of a second slot, thesecond slot including at least the second symbol and a second referencesignal, the first information and the second information beingrepetitions.

In another aspect of the disclosure, a non-transitory computer-readablestorage medium storing computer executable code for wirelesscommunication, with a first wireless device, at a second wireless deviceis provided. The code, when executed, may cause a processor to transmit,to the first wireless device, first information at a first symbol of afirst slot, the first slot including at least the first symbol and afirst reference signal. The example code, when executed, may also causethe processor to transmit second information at a second symbol of asecond slot, the second slot including at least the second symbol and asecond reference signal, the first information and the secondinformation being repetitions.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIG. 2 illustrates example aspects of a sidelink slot structure.

FIG. 3 is a diagram illustrating an example of a first device and asecond device involved in wireless communication based, e.g., onsidelink.

FIG. 4 illustrates example aspects of sidelink communication betweendevices, in accordance with aspects presented herein.

FIG. 5A illustrates an example sidelink control channel demodulationreference signal pattern in a frequency-domain, in accordance withaspects presented herein.

FIG. 5B illustrates example slot structures in a time-domain, inaccordance with aspects presented herein.

FIG. 6 illustrates an example sidelink DMRS bundling window includingslots containing DMRS that may be used for channel estimation, inaccordance with aspects presented herein.

FIG. 7A illustrates an example signal that may be transmitted in a firstslot and a second slot, in accordance with aspects presented herein.

FIG. 7B illustrates the example signal of FIG. 7A transmitted in a firstscenario maintaining phase continuity between the first slot and thesecond slot, in accordance with aspects presented herein.

FIG. 7C illustrates the example signal of FIG. 7A transmitted in asecond scenario including a phase jump between the first slot and thesecond slot, in accordance with aspects presented herein.

FIG. 8 illustrates examples for mapping tones to a constellation, inaccordance with aspects presented herein.

FIG. 9A illustrates an example slot including 14 symbols, in accordancewith aspects presented herein.

FIG. 9B illustrates an example including back-to-back slots, inaccordance with aspects presented herein.

FIG. 10 illustrates an example of phase jump estimation using anautomatic gain control symbol, in accordance with aspects presentedherein.

FIG. 11 illustrates an example of phase jump estimation using a lastdata symbol of a preceding slot, in accordance with aspects presentedherein.

FIG. 12 illustrates an example of phase jump estimation using controlDMRS, in accordance with aspects presented herein.

FIG. 13 illustrates another example of phase jump estimation usingcontrol DMRS, in accordance with aspects presented herein.

FIG. 14 is an example communication flow between a first wireless deviceand a second wireless device, in accordance with the teachings disclosedherein.

FIG. 15 is a flowchart of a method of wireless communication at a firstwireless device, in accordance with aspects presented herein.

FIG. 16 is a flowchart of another method of wireless communication at afirst wireless device, in accordance with aspects presented herein.

FIG. 17 is a diagram illustrating an example of a hardwareimplementation for an example apparatus, in accordance with aspectspresented herein.

FIG. 18 is a flowchart of a method of wireless communication at a secondwireless device, in accordance with aspects presented herein.

FIG. 19 is a flowchart of another method of wireless communication at asecond wireless device, in accordance with aspects presented herein.

FIG. 20 is a diagram illustrating an example of a hardwareimplementation for an example apparatus.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, etc. (collectively referred to as “elements”).These elements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

Accordingly, in one or more example aspects, the functions described maybe implemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of the types ofcomputer-readable media, or any other medium that can be used to storecomputer executable code in the form of instructions or data structuresthat can be accessed by a computer.

While aspects and implementations are described in this application byillustration to some examples, those skilled in the art will understandthat additional implementations and use cases may come about in manydifferent arrangements and scenarios. Innovations described herein maybe implemented across many differing platform types, devices, systems,shapes, sizes, and packaging arrangements. For example, implementationsand/or uses may come about via integrated chip implementations and othernon-module-component based devices (e.g., end-user devices, vehicles,communication devices, computing devices, industrial equipment,retail/purchasing devices, medical devices, artificial intelligence(AI)-enabled devices, etc.). While some examples may or may not bespecifically directed to use cases or applications, a wide assortment ofapplicability of described innovations may occur. Implementations mayrange a spectrum from chip-level or modular components to non-modular,non-chip-level implementations and further to aggregate, distributed, ororiginal equipment manufacturer (OEM) devices or systems incorporatingone or more aspects of the described innovations. In some practicalsettings, devices incorporating described aspects and features may alsoinclude additional components and features for implementation andpractice of claimed and described aspect. For example, transmission andreception of wireless signals necessarily includes a number ofcomponents for analog and digital purposes (e.g., hardware componentsincluding antenna, RF-chains, power amplifiers, modulators, buffer,processor(s), interleaver, adders/summers, etc.). It is intended thatinnovations described herein may be practiced in a wide variety ofdevices, chip-level components, systems, distributed arrangements,aggregated or disaggregated components, end-user devices, etc. ofvarying sizes, shapes, and constitution.

In some wireless communications systems, data transmissions by atransmitting device may be accompanied by demodulation reference signals(DMRS), which may be used by a receiving device to support demodulatingor otherwise decoding the data transmissions. In some cases, techniquesfor bundling of demodulation reference signals may be supported, and thereceiving device may be configured to assume that the same precoder isused by a transmitting device across the data channels of differentscheduling units. For example, when demodulation reference signals aretransmitted over different time intervals or different antenna ports,demodulation reference signals over different time instants or antennaports can be coherently filtered or otherwise processed by a receivingdevice to enhance the accuracy or efficiency of channel estimation forphysical channel transmissions.

Sidelink DMRS bundling may refer to transmitting a sidelink DMRS overmultiple slots for coherent combining. Coherent combining may refer toincreasing a power of a signal by combining the signal across slots. Forexample, the signal in a first slot may be added to a signal in a secondslot to perform coherent combining (e.g., the signal in the first slotand the signal in the second slot may be aggregated). Sidelink DMRSbundling may be used in scenarios in which the signal-to-noise ratio(SNR) at a receiving device is low, which may reduce the ability of thereceiving device to accurately estimate channel conditions using DMRS inone slot. When sidelink DRMS bundling is employed, the receiving devicemay use DMRS symbols across multiple slots (e.g., within a bundlingwindow) to improve the channel estimation, for example, in scenarioswith low SNR. For example, the receiving device may use DMRS from afirst slot DMRS symbol and DMRS from a second slot DMRS symbol toimprove channel estimation across the slots of the bundling window.

To perform sidelink DMRS bundling, the channel within the bundlingwindow is assumed to be the same. For example, if the first slot isassociated with a first channel and the second slot is associated with asecond channel different than the first channel, then conditions acrossthe first slot and the second slot may be different such that combiningDMRS symbols across the slots may not provide a useful estimation ofchannel conditions. For example, in high mobility scenarios, such asV2X, the high Doppler effect may result in fast changing channels, whichmay reduce the benefits of performing sidelink DMRS bundling.

Thus, sidelink DMRS bundling may be performed in low mobility scenarioswith slow changing channels. For example, in a low mobility scenario,the channel may change slowly due to low Doppler effect. In suchscenarios, the DMRS at the first slot DMRS symbol and the second slotDMRS symbol may be the same and, thus, coherent combining of the DMRSsymbols may be used to estimate the channel conditions.

However, the DMRS at the first slot DMRS symbol and the second slot DMRSsymbol may be different due to phase jump. A phase jump may refer to achange in phase across slots. For example, a transmitting device maytransmit a same OFDM symbol “A” at the first slot DMRS symbol and thesecond slot DMRS symbol. A random phase term may be introduced by RFcomponents at the transmitting device and/or the receiving device. Whenthe phase term is the same at the first slot and the second slot, thenphase continuity is maintained from the first slot to the second slot.When the phase term is different, then there is a phase jump from thefirst slot to the second slot.

When a receiving device estimates channel conditions for the first slotand the second slot separately, then different random phase terms may beacceptable. For example, when the receiving device estimates a firstchannel condition based on the DMRS of the first slot and also estimatesa second channel condition based on the DMRS of the second slot, thendifferent random phase terms across the slots do not impact therespective channel condition estimates. However, when DMRS symbols arebeing combined across multiple slots to estimate the condition of thechannel (e.g., across the slots of the bundling window), then thedifferent random phase terms may reduce the accuracy of the conditionestimate for the channel and/or may prevent performing DMRS bundlingacross the slots of the bundling window. By accurately estimatingchannel conditions, a higher MCS may be selected, which may increasethroughput.

When phase continuity is broken between the first slot and the secondslot, the receiving device may receive a second slot signal thatincludes a phase jump. The phase jump may be introduced by thetransmitting device and/or the receiving device.

In addition to phase jump, a signal may incur phase noise. Phase noisemay be introduced due to different clocks in each device (e.g., atransmitting device and/or a receiving device). If the clock is offsetfrom a “true time,” then the offset introduces a phase noise.

When phase noise occurs, each of the tones of a symbol are rotated dueto the phase noise. For example, each of the tones may be rotated by asame amount, which may be referred to as a common phase error (CPE).

While CPE may represent the rotation experienced by each tone in asymbol, the phase noise may be time-varying. That is, each symbol mayexperience a different CPE. However, the phase noise may be slowlytime-varying. For example, the CPE experienced by neighboring symbolsmay be similar. As used herein, two CPEs may be referred to as “similar”when the difference between a first CPE and a second CPE is less than athreshold. For example, a threshold may include a particular quantity ofdegrees (e.g., one degree, two degree, etc.) with respect to phaseand/or a particular value in magnitude (e.g., one decibel (dB), two dB,etc.).

While phase noise and phase jump may both impact a signal, a signaldistortion due to phase noise and a signal distortion due to phase jumpare different. However, if the CPE at two symbols can be determined tobe the same, then phase error difference determined between the twosymbols can be attributed to phase jump.

Aspects disclosed herein provide techniques for estimating the phasejump between a first slot and a second slot. In some examples, byestimating the phase jump, the receiving device may remove the phasejump to generate a copy of a signal at the first slot. The receivingdevice may then use the received signal of the first slot and the copyof the signal of the first slot with phase jump removed to perform jointchannel estimation, such as DMRS bundling.

Additionally, and as described herein, the CPE experienced at twosymbols may be similar when the two symbols are neighboring symbols.Moreover, if the CPE is the same at the two symbols, then the differencein phase error difference between a phase error determined at the secondsymbol and a phase error determined at the first symbol may beattributed to phase jump. Thus, aspects disclosed herein providetechniques for performing DMRS bundling over a first slot and a secondslot that are a threshold quantity of slots apart and using a firstsymbol of the first slot and a second symbol of the second slot that areassociated with a similar CPE to estimate the phase jump.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, an Evolved Packet Core (EPC) 160, and anothercore network 190 (e.g., a 5G Core (5GC)). The base stations 102 mayinclude macrocells (high power cellular base station) and/or small cells(low power cellular base station). The macrocells include base stations.The small cells include femtocells, picocells, and microcells.

A link between a UE 104 and a base station 102 or 180 may be establishedas an access link, e.g., using a Uu interface. Other communication maybe exchanged between wireless devices based on sidelink. For example,some UEs 104 may communicate with each other directly using adevice-to-device (D2D) communication link 158. In some examples, the D2Dcommunication link 158 may use the DL/UL WWAN spectrum. The D2Dcommunication link 158 may use one or more sidelink channels, such as aphysical sidelink broadcast channel (PSBCH), a physical sidelinkdiscovery channel (PSDCH), a physical sidelink shared channel (PSSCH),and a physical sidelink control channel (PSCCH). D2D communication maybe through a variety of wireless D2D communications systems, such as forexample, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute ofElectrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

Some examples of sidelink communication may include vehicle-basedcommunication devices that can communicate from vehicle-to-vehicle(V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-basedcommunication device to road infrastructure nodes such as a Road SideUnit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-basedcommunication device to one or more network nodes, such as a basestation), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything(C-V2X), and/or a combination thereof and/or with other devices, whichcan be collectively referred to as vehicle-to-anything (V2X)communications. Sidelink communication may be based on V2X or other D2Dcommunication, such as Proximity Services (ProSe), etc. In addition toUEs, sidelink communication may also be transmitted and received byother transmitting and receiving devices, such as Road Side Unit (RSU)107, etc. Sidelink communication may be exchanged using a PC5 interface,such as described in connection with the example in FIG. 2 . Althoughthe following description, including the example slot structure of FIG.2 , may provide examples for sidelink communication in connection with5G NR, the concepts described herein may be applicable to other similarareas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Referring again to FIG. 1 , in certain aspects, a UE 104, or otherdevice communicating based on sidelink (e.g., a first wireless device),may include a phase jump estimation component 198 configured to receive,from a second wireless device, first information at a first symbol of afirst slot, the first slot including at least the first symbol and afirst reference signal. The example phase jump estimation component 198may also be configured to receive second information at a second symbolof a second slot, the second slot including at least the second symboland a second reference signal, the first information and the secondinformation being repetitions. Additionally, the example phase jumpestimation component 198 may be configured to generate a first referencesignal copy based at least on the second reference signal and a phasejump between the first slot and the second slot, the phase jump based ona first phase error associated with the first symbol and a second phaseerror associated with the second symbol. The example phase jumpestimation component 198 may also be configured to perform channelestimation across the first slot and the second slot based on anaggregation of the first reference signal and the first reference signalcopy.

Still referring to FIG. 1 , in certain a UE 104, or other devicecommunicated based on sidelink (e.g., a second wireless device), mayinclude a repetition component 199 configured to transmit, to the firstwireless device, first information at a first symbol of a first slot,the first slot including at least the first symbol and a first referencesignal. The example repetition component 199 may also be configured totransmit second information at a second symbol of a second slot, thesecond slot including at least the second symbol and a second referencesignal, the first information and the second information beingrepetitions.

The aspects presented herein may enable a first wireless device toestimate a phase jump between a first slot and a second slot, which mayfacilitate improving communication performance, for example, byimproving channel estimation and increasing throughput.

Although the following description provides examples directed to 5G NR(and, in particular, to sidelink communication), the concepts describedherein may be applicable to other similar areas, such as LTE, LTE-A,CDMA, GSM, and/or other wireless technologies, in which a first wirelessdevice may communicate with a second wireless device, such as in a Uulink.

Additionally, while the following description provides examples ofestimating a phase jump to facilitate performing DMRS bundling, theconcepts described herein may be applicable to other similar areas inwhich a first wireless device may perform joint channel estimation.

The base stations 102 configured for 4G LTE (collectively referred to asEvolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (E-UTRAN)) may interface with the EPC 160 throughfirst backhaul links 132 (e.g., S1 interface). The base stations 102configured for 5G NR (collectively referred to as Next Generation RAN(NG-RAN)) may interface with core network 190 through second backhaullinks 184. In addition to other functions, the base stations 102 mayperform one or more of the following functions: transfer of user data,radio channel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160 or corenetwork 190) with each other over third backhaul links 134 (e.g., X2interface). The first backhaul links 132, the second backhaul links 184,and the third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacrocells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 and/or downlink (DL)(also referred to as forward link) transmissions from a base station 102to a UE 104. The communication links 120 may use multiple-input andmultiple-output (MIMO) antenna technology, including spatialmultiplexing, beamforming, and/or transmit diversity. The communicationlinks may be through one or more carriers. The base stations 102/UEs 104may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz)bandwidth per carrier allocated in a carrier aggregation of up to atotal of Yx MHz (x component carriers) used for transmission in eachdirection. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or fewer carriers may be allocated for DL than for UL). Thecomponent carriers may include a primary component carrier and one ormore secondary component carriers. A primary component carrier may bereferred to as a primary cell (PCell) and a secondary component carriermay be referred to as a secondary cell (SCell).

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154, e.g., in a 5 GHz unlicensed frequency spectrumor the like. When communicating in an unlicensed frequency spectrum, theSTAs 152/AP 150 may perform a clear channel assessment (CCA) prior tocommunicating in order to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ NR and use the same unlicensed frequencyspectrum (e.g., 5 GHz, or the like) as used by the Wi-Fi AP 150. Thesmall cell 102′, employing NR in an unlicensed frequency spectrum, mayboost coverage to and/or increase capacity of the access network.

The electromagnetic spectrum is often subdivided, based onfrequency/wavelength, into various classes, bands, channels, etc. In 5GNR, two initial operating bands have been identified as frequency rangedesignations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz).Although a portion of FR1 is greater than 6 GHz, FR1 is often referredto (interchangeably) as a “sub-6 GHz” band in various documents andarticles. A similar nomenclature issue sometimes occurs with regard toFR2, which is often referred to (interchangeably) as a “millimeter wave”band in documents and articles, despite being different from theextremely high frequency (EHF) band (30 GHz-300 GHz) which is identifiedby the International Telecommunications Union (ITU) as a “millimeterwave” band.

The frequencies between FR1 and FR2 are often referred to as mid-bandfrequencies. Recent 5G NR studies have identified an operating band forthese mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25 GHz). Frequency bands falling within FR3 may inherit FR1characteristics and/or FR2 characteristics, and thus may effectivelyextend features of FR1 and/or FR2 into mid-band frequencies. Inaddition, higher frequency bands are currently being explored to extend5G NR operation beyond 52.6 GHz. For example, three higher operatingbands have been identified as frequency range designations FR4a or FR4-1(52.6 GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25 GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

With the above aspects in mind, unless specifically stated otherwise, itshould be understood that the term “sub-6 GHz” or the like if usedherein may broadly represent frequencies that may be less than 6 GHz,may be within FR1, or may include mid-band frequencies. Further, unlessspecifically stated otherwise, it should be understood that the term“millimeter wave” or the like if used herein may broadly representfrequencies that may include mid-band frequencies, may be within FR2,FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.

A base station 102, whether a small cell 102′ or a large cell (e.g.,macro base station), may include and/or be referred to as an eNB, gNodeB(gNB), or another type of base station. Some base stations, such as gNB180 may operate in a traditional sub 6 GHz spectrum, in millimeter wavefrequencies, and/or near millimeter wave frequencies in communicationwith the UE 104. When the gNB 180 operates in millimeter wave or nearmillimeter wave frequencies, the gNB 180 may be referred to as amillimeter wave base station. The millimeter wave base station 180 mayutilize beamforming 182 with the UE 104 to compensate for the path lossand short range. The base station 180 and the UE 104 may each include aplurality of antennas, such as antenna elements, antenna panels, and/orantenna arrays to facilitate the beamforming. Similarly, beamforming maybe applied for sidelink communication, e.g., between UEs.

The base station 180 may transmit a beamformed signal to the UE 104 inone or more transmit directions 182′. The UE 104 may receive thebeamformed signal from the base station 180 in one or more receivedirections 182″. The UE 104 may also transmit a beamformed signal to thebase station 180 in one or more transmit directions. The base station180 may receive the beamformed signal from the UE 104 in one or morereceive directions. The base station 180/UE 104 may perform beamtraining to determine the best receive and transmit directions for eachof the base station 180/UE 104. The transmit and receive directions forthe base station 180 may or may not be the same. The transmit andreceive directions for the UE 104 may or may not be the same. Althoughthis example is described for the base station 180 and UE 104, theaspects may be similarly applied between a first and second device(e.g., a first and second UE) for sidelink communication.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMEs 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services. The BM-SC 170 may provide functionsfor MBMS user service provisioning and delivery. The BM-SC 170 may serveas an entry point for content provider MBMS transmission, may be used toauthorize and initiate MBMS Bearer Services within a public land mobilenetwork (PLMN), and may be used to schedule MBMS transmissions. The MBMSGateway 168 may be used to distribute MBMS traffic to the base stations102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN)area broadcasting a particular service, and may be responsible forsession management (start/stop) and for collecting eMBMS relatedcharging information.

The core network 190 may include an Access and Mobility ManagementFunction (AMF) 192, other AMFs 193, a Session Management Function (SMF)194, and a User Plane Function (UPF) 195. The AMF 192 may be incommunication with a Unified Data Management (UDM) 196. The AMF 192 isthe control node that processes the signaling between the UEs 104 andthe core network 190. Generally, the AMF 192 provides QoS flow andsession management. All user Internet protocol (IP) packets aretransferred through the UPF 195. The UPF 195 provides UE IP addressallocation as well as other functions. The UPF 195 is connected to theIP Services 197. The IP Services 197 may include the Internet, anintranet, an IP Multimedia Subsystem (IMS), a Packet Switch (PS)Streaming (PSS) Service, and/or other IP services.

The base station may include and/or be referred to as a gNB, Node B,eNB, an access point, a base transceiver station, a radio base station,a radio transceiver, a transceiver function, a basic service set (BSS),an extended service set (ESS), a transmit reception point (TRP), or someother suitable terminology. The base station 102 provides an accesspoint to the EPC 160 or core network 190 for a UE 104. Examples of UEs104 include a cellular phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal digital assistant (PDA), asatellite radio, a global positioning system, a multimedia device, avideo device, a digital audio player (e.g., MP3 player), a camera, agame console, a tablet, a smart device, a wearable device, a vehicle, anelectric meter, a gas pump, a large or small kitchen appliance, ahealthcare device, an implant, a sensor/actuator, a display, or anyother similar functioning device. Some of the UEs 104 may be referred toas IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heartmonitor, etc.). The UE 104 may also be referred to as a station, amobile station, a subscriber station, a mobile unit, a subscriber unit,a wireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable terminology.

FIG. 2 includes diagrams 200 and 210 illustrating example aspects ofslot structures that may be used for sidelink communication (e.g.,between UEs 104, RSU 107, etc.). The slot structure may be within a5G/NR frame structure in some examples. In other examples, the slotstructure may be within an LTE frame structure. Although the followingdescription may be focused on 5G NR, the concepts described herein maybe applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, andother wireless technologies. The example slot structure in FIG. 2 ismerely one example, and other sidelink communication may have adifferent frame structure and/or different channels for sidelinkcommunication. A frame (10 ms) may be divided into 10 equally sizedsubframes (1 ms). Each subframe may include one or more time slots.Subframes may also include mini-slots, which may include 7, 4, or 2symbols. Each slot may include 14 or 12 symbols, depending on whetherthe cyclic prefix (CP) is normal or extended. For normal CP, each slotmay include 14 symbols, and for extended CP, each slot may include 12symbols. The symbols may be CP orthogonal frequency divisionmultiplexing (OFDM) (CP-OFDM) symbols. The symbols may be CP-OFDMsymbols (for high throughput scenarios) or discrete Fourier transform(DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as singlecarrier frequency-division multiple access (SC-FDMA) symbols) (for powerlimited scenarios; limited to a single stream transmission). The numberof slots within a subframe is based on the CP and the numerology. Thenumerology defines the subcarrier spacing (SCS) and, effectively, thesymbol length/duration, which is equal to 1/SCS.

SCS μ Δf = 2^(μ) · 15 [kHz] Cyclic prefix 0 15 Normal 1 30 Normal 2 60Normal, Extended 3 120 Normal 4 240 Normal

For normal CP (14 symbols/slot), different numerologies μ 0 to 4 allowfor 1, 2, 4, 8, and 16 slots, respectively, per subframe. For extendedCP, the numerology 2 allows for 4 slots per subframe. Accordingly, fornormal CP and numerology μ, there are 14 symbols/slot and 2^(μ)slots/subframe. The subcarrier spacing may be equal to 2^(μ)*15 kHz,where μ is the numerology 0 to 4. As such, the numerology μ=0 has asubcarrier spacing of 15 kHz and the numerology μ=4 has a subcarrierspacing of 240 kHz. The symbol length/duration is inversely related tothe subcarrier spacing. FIG. 2 provides an example of normal CP with 14symbols per slot. Within a set of frames, there may be one or moredifferent bandwidth parts (BWPs) that are frequency divisionmultiplexed. Each BWP may have a particular numerology and CP (normal orextended).

Diagram 200 illustrates a single resource block of a single slottransmission, e.g., which may correspond to a 0.5 ms transmission timeinterval (TTI). A physical sidelink control channel may be configured tooccupy multiple physical resource blocks (PRBs), e.g., 10, 12, 15, 20,or 25 PRBs. The PSCCH may be limited to a single sub-channel. A PSCCHduration may be configured to be 2 symbols or 3 symbols, for example. Asub-channel may comprise 10, 15, 20, 25, 50, 75, or 100 PRBs, forexample. The resources for a sidelink transmission may be selected froma resource pool including one or more subchannels. As a non-limitingexample, the resource pool may include between 1-27 subchannels. A PSCCHsize may be established for a resource pool, e.g., as between 10-100% ofone subchannel for a duration of 2 symbols or 3 symbols. The diagram 210in FIG. 2 illustrates an example in which the PSCCH occupies about 50%of a subchannel, as one example to illustrate the concept of PSCCHoccupying a portion of a subchannel. The physical sidelink sharedchannel (PSSCH) occupies at least one subchannel. The PSCCH may includea first portion of sidelink control information (SCI), and the PSSCH mayinclude a second portion of SCI in some examples.

A resource grid may be used to represent the frame structure. Each timeslot may include a resource block (RB) (also referred to as physical RBs(PRBs)) that extends 12 consecutive subcarriers. The resource grid isdivided into multiple resource elements (REs). The number of bitscarried by each RE depends on the modulation scheme. As illustrated inFIG. 2 , some of the REs may include control information in PSCCH andsome REs may include demodulation RS (DMRS). At least one symbol may beused for feedback. FIG. 2 illustrates examples with two symbols for aphysical sidelink feedback channel (PSFCH) with adjacent gap symbols. Asymbol prior to and/or after the feedback may be used for turnaroundbetween reception of data and transmission of the feedback. The gapenables a device to switch from operating as a transmitting device toprepare to operate as a receiving device, e.g., in the following slot.Data may be transmitted in the remaining REs, as illustrated. The datamay comprise the data message described herein. The position of any ofthe data, DMRS, SCI, feedback, gap symbols, and/or LBT symbols may bedifferent than the example illustrated in FIG. 2 . Multiple slots may beaggregated together in some aspects.

FIG. 3 is a block diagram 300 of a first wireless communication device310 in communication with a second wireless communication device 350.The communication may be based on sidelink or an access link. In someexamples, the wireless communication devices 310, 350 may communicatebased on V2X or other D2D communication. In other aspects, the wirelesscommunication devices 310, 350 may communicate over an access link basedon uplink and downlink transmissions. The communication may be based onsidelink using a PC5 interface (e.g., between two UEs). Thecommunication may be based on an access link using a Uu interface (e.g.,between a base station and a UE). The wireless communication devices310, 350 may comprise a UE, an RSU, a base station, etc. In someimplementations, the first wireless communication device 310 maycorrespond to a base station and the second wireless communicationdevice 350 may correspond to a UE.

As shown in FIG. 3 , the first wireless communication device 310includes a transmit processor (TX processor 316), a transceiver 318including a transmitter 318 a and a receiver 318 b, antennas 320, areceive processor (RX processor 370), a channel estimator 374, acontroller/processor 375, and memory 376. The example second wirelesscommunication device 350 includes antennas 352, a transceiver 354including a transmitter 354 a and a receiver 354 b, an RX processor 356,a channel estimator 358, a controller/processor 359, memory 360, and aTX processor 368. In other examples, the first wireless communicationdevice 310 and/or the second wireless communication device 350 mayinclude additional or alternative components.

Packets may be provided to the controller/processor 375 that implementslayer 3 and layer 2 functionality. Layer 3 includes a radio resourcecontrol (RRC) layer, and layer 2 includes a packet data convergenceprotocol (PDCP) layer, a radio link control (RLC) layer, and a mediumaccess control (MAC) layer.

The TX processor 316 and the RX processor 370 implement layer 1functionality associated with various signal processing functions. Layer1, which includes a physical (PHY) layer, may include error detection onthe transport channels, forward error correction (FEC) coding/decodingof the transport channels, interleaving, rate matching, mapping ontophysical channels, modulation/demodulation of physical channels, andMIMO antenna processing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from the channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe second wireless communication device 350. Each spatial stream maythen be provided to a different antenna 320 via a separate transmitter318 a. Each transmitter 318 a may modulate a radio frequency (RF)carrier with a respective spatial stream for transmission.

At the second wireless communication device 350, each receiver 354 breceives a signal through its respective antenna 352. Each receiver 354b recovers information modulated onto an RF carrier and provides theinformation to the RX processor 356. The TX processor 368 and the RXprocessor 356 implement layer 1 functionality associated with varioussignal processing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the second wireless communication device 350. If multiple spatialstreams are destined for the second wireless communication device 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe first wireless communication device 310. These soft decisions may bebased on channel estimates computed by the channel estimator 358. Thesoft decisions are then decoded and deinterleaved to recover the dataand control signals that were originally transmitted by the firstwireless communication device 310 on the physical channel. The data andcontrol signals are then provided to the controller/processor 359, whichimplements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with the memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. The controller/processor 359 may providedemultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing. The controller/processor 359 is also responsible for errordetection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with thetransmission by the first wireless communication device 310, thecontroller/processor 359 may provide RRC layer functionality associatedwith system information (e.g., MIB, SIBs) acquisition, RRC connections,and measurement reporting; PDCP layer functionality associated withheader compression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto TBs,demultiplexing of MAC SDUs from TBs, scheduling information reporting,error correction through HARQ, priority handling, and logical channelprioritization.

Channel estimates derived by the channel estimator 358 from a referencesignal or feedback transmitted by the first wireless communicationdevice 310 may be used by the TX processor 368 to select the appropriatecoding and modulation schemes, and to facilitate spatial processing. Thespatial streams generated by the TX processor 368 may be provided todifferent antenna 352 via separate transmitters 354 a. Each transmitter354 a may modulate an RF carrier with a respective spatial stream fortransmission.

The transmission is processed at the first wireless communication device310 in a manner similar to that described in connection with thereceiver function at the second wireless communication device 350. Eachreceiver 318 b receives a signal through its respective antenna 320.Each receiver 318 b recovers information modulated onto an RF carrierand provides the information to the RX processor 370.

The controller/processor 375 can be associated with the memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. The controller/processor 375 providesdemultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signalprocessing. The controller/processor 375 is also responsible for errordetection using an ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and thecontroller/processor 359 may be configured to perform aspects inconnection with the phase jump estimation component 198 of FIG. 1 .

At least one of the TX processor 316, the RX processor 370, and thecontroller/processor 375 may be configured to perform aspects inconnection with the repetition component 199 of FIG. 1 .

FIG. 4 illustrates an example 400 of sidelink communication betweendevices, as presented herein. The communication may be based on a slotstructure comprising aspects described in connection with FIG. 2 oranother sidelink structure. For example, a first UE 402 may transmit asidelink transmission 414, e.g., comprising a control channel (e.g.,PSCCH) and/or a corresponding data channel (e.g., PSSCH), that may bereceived by a second UE 404 and/or a sidelink transmission 415 that maybe received by a third UE 406 directly from the first UE 402, e.g.,without being transmitting through a base station. Additionally, oralternatively, an RSU 407 may receive communication from and/or transmitcommunication to the UEs 402, 404, 406. As shown in FIG. 4 , the RSU 407may transmit a sidelink transmission 418 to the first UE 402.

The UEs 402, 404, 406 and/or the RSU 407 may each be capable ofoperating as a transmitting device in addition to operating as areceiving device. For example, in the example of FIG. 4 , the third UE406 is illustrated as transmitting a sidelink transmission 416 that isreceived by the first UE 402. One or more of the sidelink transmissions414, 415, 416, 418 may be broadcast or multicast to nearby devices. Forexample, the first UE 402 may transmit communication intended forreceipt by other UEs within a range 401 of the first UE 402. In otherexamples, one or more of the sidelink transmissions 414, 415, 416, 418may be groupcast to nearby devices that are a member of a group. Inother examples, one or more of the sidelink transmissions 414, 415, 416,418 may be unicast from one UE to another UE.

A sidelink transmission may provide sidelink control information (SCI)including information to facilitate decoding the corresponding datachannel. The SCI may also include information that a receiving devicemay use to avoid interference. For example, the SCI may indicatereserved time resources and/or reserved frequency resources that will beoccupied by the data transmission, and may be indicated in a controlmessage from the transmitting device.

One or more of the UEs 402, 404, 406 and/or the RSU 407 may include aphase jump estimation component, similar to the phase jump estimationcomponent 198 described in connection with FIG. 1 . One or more of theUEs 402, 404, 406 and/or the RSU 407 may additionally or alternativelyinclude a reference signal component, similar to the repetitioncomponent 199 described in connection with FIG. 1 .

In some wireless communications systems, data transmissions by atransmitting device may be accompanied by demodulation referencesignals, which may be used by a receiving device to support demodulatingor otherwise decoding the data transmissions. The transmitting deviceand the receiving device may each use a precoding configuration, whichmay be negotiated or otherwise communicated between the transmittingdevice and the receiving device. Aspects of the precoding configurationmay support encoding the data transmission by the transmitting deviceand decoding the encoded data transmission by the receiving device. Insome cases, techniques for bundling of demodulation reference signalsmay be supported, and the receiving device may be configured to assumethat the same precoder is used by a transmitting device across the datachannels of different scheduling units. For example, when demodulationreference signals are coherently transmitted over different timeintervals or different antenna ports, demodulation reference signalsover different time instants or antenna ports can be coherently filteredor otherwise processed by a receiving device to enhance the accuracy orefficiency of channel estimation for physical channel transmissions.

Demodulation reference signals may be transmitted in combination withphysical control channel transmissions and physical data channeltransmissions. For example, in sidelink communications, demodulationreference signals may be transmitted with PSCCH transmissions and/orPSSCH transmissions. With respect to PSCCH transmissions, demodulationreference signals may be present in PSCCH symbols and may be placed in apattern. For example, FIG. 5A illustrates an example PSCCH DMRS pattern500 in a frequency-domain (FD). The example PSCCH DMRS pattern 500includes DMRS resource elements 502 and PSCCH resource elements 504. Inthe illustrated example PSCCH DMRS pattern 500 of FIG. 5A, the DMRSresource elements 502 are placed at every fourth resource element of aPSCCH symbol 506 (e.g., a symbol containing PSSCH resource elements).However, in other examples, the positioning of DMRS resource elements ina PSCCH symbol may be different. The DMRS resource elements 502 may bedrawn from (or derived from) a Gold sequence.

Referring to PSSCH transmissions, demodulation reference signals may bepresent in 2 symbol, 3 symbol, and 4 symbol DMRS patterns that may beconfigured or preconfigured. For example, a transmitting device mayselect a DMRS pattern and signal the selected DMRS pattern to areceiving device using SCI (e.g., a first stage SCI). Similar to theDMRS resource elements of a PSCCH transmission, the DMRS resourceelements of a PSSCH transmission may be drawn from (or derived from) aGold sequence.

FIG. 5B illustrates example slot structures 550 in a time-domain (TD).The example slot structures 550 include symbols 552 in a slot 554. Theexample slot structures 550 include three example PSSCH DMRS patterns580, 582, 584 without feedback and two example PSSCH DMRS patterns 586,588 with feedback (e.g., symbols including PSFCH 568).

Each of the symbols 552 in a slot may be associated with automatic gaincontrol (AGC) (e.g., AGC 560), control information (e.g., PSCCH 562),data (e.g. PSSCH 564), demodulation reference signals (e.g., DMRS 566),feedback (e.g., PSFCH 568), or a gap (e.g., gap 570). For example, ineach of the example PSSCH DMRS patterns 580, 582, 584, 586, 588, a firstsymbol includes AGC 560 and a last symbol is a guard symbol including agap 570. The first symbol containing AGC 560 facilitates a receivingdevice to adjust the gain of the receiver amplifier to fit the totalpower of the received signal. The total power of the received signal mayinclude the power associated with the transmission and interference(e.g., due to neighboring devices). The guard symbol including the gap570 provides a switching time to allow the receiving device tofacilitate switching between sidelink transmission/reception (and viceversa), and to facilitate switching between sidelink and downlink/uplinktransmissions (and vice versa). For example, a receiving device may usethe guard symbol to switch from a first beam to receive a transmissionto a second beam to transmit a transmission. A symbol including feedback(e.g., PSFCH 568) may include ACK/NACK feedback to facilitate HARQoperations.

In some examples, a symbol may include control information and dataand/or DMRS. For example, in a first PSSCH DMRS pattern 580 and a fourthPSSCH DMRS pattern 586, a second symbol, a third symbol, and a fourthsymbol each include a control portion (e.g., PSCCH 562) and a dataportion (e.g. PSSCH 564). In a second PSSCH DMRS pattern 582, a thirdPSSCH DMRS pattern 584, and a fifth PSSCH DMRS pattern 588, a secondsymbol includes a control portion (e.g., PSCCH 562) and a DMRS portion(e.g., DMRS 566).

The positioning of DMRS in a PSSCH transmission may be based ondifferent configuration types. In the example slot structures 550 ofFIG. 5B, a symbol (or a portion of a symbol) containing DMRS 566 may usea configuration type 1 for the DMRS in the frequency domain. Forexample, the DMRS may be positioned at every other tone. The term “tone”may refer to a frequency subcarrier of a symbol. As used herein, theterms “tone” and “resource element” may be used interchangeably.

Although not shown in the examples of FIGS. 5A and 5B, it may beappreciated that other examples may include additional or alternativePSCCH DMRS patterns and/or PSSCH DMRS patterns.

Sidelink DMRS bundling may refer to transmitting a sidelink DMRS overmultiple slots for coherent combining. Coherent combining may refer toincreasing a received power of a signal by combining the signal acrossslots. For example, the signal in a first slot may be added to a signalin a second slot to perform coherent combining (e.g., the signal in thefirst slot and the signal in the second slot may be aggregated). FIG. 6illustrates an example sidelink DMRS bundling window 600 including slotscontaining DMRS that may be used for channel estimation, as presentedherein. Sidelink DMRS bundling may be used in scenarios in which thesignal-to-noise ratio (SNR) at a receiving device is low, which mayreduce the ability of the receiving device to accurately estimatechannel conditions using DMRS in one slot. When sidelink DRMS bundlingis employed, the receiving device may use DMRS symbols across multipleslots to improve the channel estimation, for example, in scenarios withlow SNR.

In the illustrated example of FIG. 6 , a first slot 610 includes a firstslot DMRS symbol 612 and a second slot 620 includes a second slot DMRSsymbol 622. A receiving device may combine the DMRS from the first slotDMRS symbol 612 and the second slot DMRS symbol 622 to improve channelestimation across the slots of the sidelink DMRS bundling window 600.

The first slot 610 and the second slot 620 may be separated by n slots.In examples in which the value of n is zero, the first slot 610 and thesecond slot 620 may be referred to as back-to-back slots or consecutiveslots.

In the illustrated example of FIG. 6 , the first slot 610 and the secondslot 620 include phase tracking reference signals (PTRS). For example,the first slot 610 includes PTRS 614 and the second slot 620 includesPTRS 624. The PTRS 614, 624 may be used to estimate phase noise, forexample, introduced by the transmitting device and/or the receivingdevice. Although the example slots 610, 620 of FIG. 6 include the PTRS614, 624, the presence of PTRS may be based on the available bandwidthand modulation and coding scheme (MCS). For example, in scenarios inwhich the transmitting bandwidth is small or the MCS is low, then thetransmission may not include PTRS.

To perform sidelink DMRS bundling, the channel within the sidelink DMRSbundling window 600 is assumed to be the same. For example, if the firstslot 610 is associated with a first channel and the second slot 620 isassociated with a second channel different than the first channel, thenconditions across the first slot 610 and the second slot 620 may bedifferent such that combining the DMRS symbols across the slots 610, 620may be unable to provide a useful estimation of channel conditions. Forexample, in high mobility scenarios, such as V2X, the high Dopplereffect may result in fast changing channels, which may reduce thebenefits of performing sidelink DMRS bundling.

Thus, sidelink DMRS bundling may be performed in low mobility scenarioswith slow changing channels. For example, in a low mobility scenario,the channel may change slowly due to low Doppler effect. In suchscenarios, the DMRS at the first slot DMRS symbol 612 and the secondslot DMRS symbol 622 may be the same and, thus, coherent combining ofthe DMRS symbols may be used to estimate the channel conditions.

However, the DMRS at the first slot DMRS symbol 612 and the second slotDMRS symbol 622 may be different due to phase jump. A phase jump mayrefer to a change in phase across slots. For example, in the example ofFIG. 6 , a transmitting device may transmit a same OFDM symbol “A” atthe first slot DMRS symbol 612 and the second slot DMRS symbol 622.Equation 1 (below) may be a representation of the OFDM symbol “A” in thefirst slot DMRS symbol 612 as received by the receiver and Equation 2(below) may be a representation of the OFDM symbol “A” in the secondslot DMRS symbol 622 as received by the receiver.

$\begin{matrix}{{v_{1}(t)} = {e^{j\theta_{1}}{\sum_{k = 0}^{N - 1}{X_{k}e^{j2\pi{kt}/T}}}}} & {{Equation}1}\end{matrix}$ $\begin{matrix}{{v_{2}(t)} = {e^{j\theta_{2}}{\sum_{k = 0}^{N - 1}{X_{k}e^{j2\pi{kt}/T}}}}} & {{Equation}2}\end{matrix}$

In the examples of Equation 1 and Equation 2, a first term

$``{\Sigma_{k = 0}^{N - 1}X_{k}e^{j2\pi{kt}/T}}"$represents the OFDM symbol “A” in the time-domain. A second term “e^(jθ)^(n) ” represents a random phase term. The random phase term “e^(jθ)^(n) ” may be introduced by RF components at the transmitting deviceand/or the receiving device unbeknownst to the transmitting device orreceiving device processors. When the phase term is the same at thefirst slot 610 and the second slot 620 (e.g., θ₁=θ₂), then phasecontinuity is maintained from the first slot 610 to the second slot 620.When the phase term is different (e.g., θ₁≠θ₂), then there is a phasejump from the first slot 610 to the second slot 620. Equation 3 (below)may be used to estimate the phase jump from the first slot 610 to thesecond slot 620.phase jump=θ₂−θ₁Equation 3

Even though the phase terms associated with the first slot 610 and thesecond slot 620 are random, in some examples, they may be the same. Insuch examples, phase continuity is maintained form the first slot 610 tothe second slot 620. In some examples, a transmitting device may havethe capability to maintain phase continuity by setting the phase termsto be equal (e.g., θ₁=θ₂). However, some transmitting devices may nothave the capability to maintain phase continuity by setting the phaseterms to be equal.

When a receiving device estimates channel conditions for the first slot610 and the second slot 620 separately, then different random phaseterms may be acceptable. For example, when the receiving deviceestimates a first channel condition based on the DMRS of the first slot610 and also estimates a second channel condition based on the DMRS ofthe second slot 620, then different random phase terms across the slots610, 620 do not impact the respective channel condition estimates.However, when DMRS symbols are being combined across multiple slots toestimate the condition of the channel (e.g., across the slots of thesidelink DMRS bundling window 600), then the different random phaseterms may reduce the accuracy of the condition estimate for the channeland/or may prevent performing DMRS bundling across the slots of thesidelink DMRS bundling window 600. By accurately estimating channelconditions, a higher MCS may be selected, which may increase throughput.

For example, FIG. 7A illustrates an example signal 700 that may betransmitted in a first scenario maintaining phase continuity and asecond scenario including a phase jump, as presented herein. In theillustrated example of FIG. 7A, the signal 700 may represent a signaltransmitted in a first slot 702 and that is repeated in a second slot704. FIG. 7B illustrates the example signal transmitted in a firstscenario 710 maintaining phase continuity between the first slot 702 andthe second slot 704, as presented herein. FIG. 7C illustrates theexample signal transmitted in a second scenario 720 including a phasejump between the first slot 702 and the second slot 704, as presentedherein. In the examples of FIGS. 7A, 7B, and 7C, the channel is the sameover the first slot 702 and the second slot 704.

In the example first scenario 710 of FIG. 7B, phase continuity ismaintained from the first slot 702 to the second slot 704. For example,a receiving device may receive a first slot signal 712 that is thesignal 700 modified by a term “a,” as shown in FIG. 7B. With phasecontinuity maintained between the first slot 702 and the second slot704, in the example first scenario 710, the receiving device may receivea second slot signal 714 that is the signal 700 modified by the term“a.” Thus, as shown in the example first scenario 710 of FIG. 7B, whenphase continuity is maintained, the first slot signal 712 and the secondslot signal 714 are a same signal (e.g., the second slot signal 714 maybe a copy of the first slot signal 712).

In the example second scenario 720 of FIG. 7C, phase continuity is notmaintained from the first slot 702 to the second slot 704 and a phasejump occurs. For example, the receiving device may receive a first slotDMRS signal 722 that is the signal 700 modified by the term “a,” asshown in FIG. 7 . With phase continuity broken between the first slot702 and the second slot 704, the receiving device may receive a secondslot DMRS signal 724 that includes a phase jump 726. The phase jump 726may be introduced by the transmitting device and/or the receivingdevice. As shown in the example second scenario 720 of FIG. 7C, eventhough the channel across the first slot 702 and the second slot 704 arethe same, the second slot DMRS signal 724 is different than the firstslot DMRS signal 722 (e.g., the second slot DMRS signal 724 is not acopy of the first slot DMRS signal 722). However, if the value of thephase jump 726 is available to the receiving device, the receivingdevice may modify the second slot DMRS signal 724 based on the phasejump 726 to generate a generated DMRS signal 728 that is a copy of thefirst slot DMRS signal 722. The receiving device may then use the firstslot DMRS signal 722 and the generated DMRS signal 728 to perform jointchannel estimation, such as DMRS bundling.

In addition to phase jump, a signal may incur phase noise. Phase noisemay be introduced due to different clocks in each device (e.g., atransmitting device and/or a receiving device). If the clock is offsetfrom a “true time,” then the offset introduces a phase noise.

FIG. 8 illustrates examples for mapping tones to a constellation, aspresented herein. In an example first scenario 800, four example tones802 are mapped to a constellation 804. In the illustrated example, thetones 802 are part of a same OFDM symbol and are mapped to theconstellation 804 using a QPSK scheme. In the example first scenario800, the tones 802 do not experience phase noise. For example, as shownin the example first scenario 800, the tones 802 are positioned to forma “clean” constellation.

In an example second scenario 820, four example tones 822 are mapped toa constellation 824. Similar to the first scenario 800, the tones 822are part of a same OFDM symbol and mapped to the constellation 824 usinga QPSK scheme. In the example second scenario 820, the tones 822experience phase noise. For example, each of the tones 822 are rotateddue to the phase noise. In some examples, there may be stretching and/orshrinking of the points to the constellation 824. Additionally, each ofthe tones 822 is rotated by a same amount, which may be referred to as acommon phase error (CPE). For example, each of the tones 822 may bemultiplied by the same CPE in a frequency domain. That is, each tone maybe rotated by a same amount (e.g., in degrees).

In some examples, a receiving device may attempt to overcome phase noiseby estimating the phase noise and then performing techniques to correctthe estimated phase noise. In some examples, a PTRS may be added to atransmission to the allow the receiving device to estimate the CPE.Thus, the PTRS may facilitate a receiving device to estimate the CPE,and the CPE refers to the rotation experienced by each tone in a symbol.

While CPE may represent the rotation experienced by each tone in asymbol, the phase noise may be time-varying. That is, each symbol mayexperience a different CPE. However, the phase noise may be slowlytime-varying. For example, the CPE experienced by neighboring symbolsmay be similar. As used herein, two CPEs may be referred to as “similar”when the difference between a first CPE and a second CPE is less than athreshold.

For example, FIG. 9A illustrates an example slot 900 including 14symbols, as presented herein. In the example of FIG. 9A, a receivingdevice may measure a first CPE 902 at a first symbol 906 and measure asecond CPE 904 at a second symbol 908. As shown in FIG. 9A, the firstsymbol 906 and the second symbol 908 are adjacent symbols (e.g.,back-to-back symbols). In such examples in which the CPEs are associatedwith adjacent (or neighboring) symbols, the CPEs may be similar. Forexample, the first CPE 902 may be similar to the second CPE 904.

In some examples, Equation 4 (below) may be used to determine the CPE.

$\begin{matrix}{{CPE} = {\frac{1}{N}{\sum_{n = 0}^{N - 1}e^{j{\theta\lbrack n\rbrack}}}}} & {{Equation}4}\end{matrix}$

In Equation 4, a first term “N” refers to an OFDM FFT size, a secondterm “n” refers to a time sample index within an OFDM symbol, and athird phase “θ[n]” refers to a phase variation at an n-th sample in anOFDM symbol.

Referring to the example slot 900, the slot 900 includes PTRS that maybe used by a receiving device to estimate the CPE experienced at asymbol. The PTRS may occupy locations at a high density in atime-domain. For example, the PTRS may be located in every 1, 2, or 4symbols. In the example of FIG. 9A, the PTRS is included in each ofsymbols 2 to 10. However, as shown in FIG. 9A, the PTRS may occupylocations at a low density in a frequency domain. For example, the PTRSmay be located in every 2 or 4 PRBs. Additionally, a transmitting devicemay forego transmitting PTRS when the transmit bandwidth is small or ifthe MCS is low.

While phase noise and phase jump may both impact a signal, a signaldistortion due to phase noise and a signal distortion due to phase jumpare different. However, if the CPE at two symbols can be determined tobe the same, then phase error difference determined between the twosymbols can be attributed to phase jump.

For example, FIG. 9B illustrates an example 950 including slots 960, 970that are back-to-back slots, as presented herein. In the illustratedexample 950, a term “A” represents a frequency-domain representation ofa signal transmitting in a symbol 962 of a first slot 960 and that isrepeated in a symbol 972 of a second slot 970. A first phase error 964represents an amount of phase error associated with the symbol 962. Inthe example of FIG. 9B, the first phase error 964 corresponds to a firstCPE (“CPE1”). A second phase error 974 represents an amount of phasenoise associated with the symbol 972 as well as phase jump introduced byRF components at the slot boundary. In the example of FIG. 9B, thesecond phase error 974 corresponds to a second CPE (“CPE2”) and a phasejump.

Equation 5 (below) may be a representation of the signal that areceiving device may receive in the symbol 962 of the first slot 960 andEquation 6 (below) may be a representation of the signal that thereceiving device may receive in the symbol 972 of the second slot 970.ν₁(t)=e ^(j*CPE) ¹ *A  Equation 5ν₂(t)=e ^(j*CPE) ² *e ^(j*phase_jump) *A  Equation 6

In the examples of Equation 5 and Equation 6, a first term “e^(j*CPE)^(n) ”, represents the phase noise experienced at the respective symbol.A second term “e^(j*phase_jump)”, represents the phase jump experiencedbetween the symbol 962 of the first slot 960 and the symbol 972 of thesecond slot 970.

Aspects disclosed herein provide techniques for estimating the phasejump between the symbol 962 and the symbol 972. By estimating the phasejump, the receiving device may remove the phase jump to generate a copyof a signal at the symbol 962. The receiving device may then use thesignal of the symbol 962 and the copy of the signal with phase jumpremoved to perform joint channel estimation, such as DMRS bundling.

For example, if the first CPE experienced at the symbol 962 and thesecond CPE experienced at the symbol 972 are similar, then Equation 7(below) may be used to estimate the phase jump.

$\begin{matrix}{\frac{e^{j \star {CPE}_{1}}*A}{e^{j \star {CPE}_{2}}*e^{j \star {{phase}\_{jump}}}*A} = e^{{- j}*{{phase}\_{jump}}}} & {{Equation}7}\end{matrix}$

Additionally, and as described above, the CPE experienced at two symbolsmay be similar when the two symbols are neighboring symbols. Based onEquation 5 and Equation 6, if the CPE is the same at the two symbols,then the difference in phase error between the second phase error 974determined at the symbol 972 and the first phase error 964 may beattributed to phase jump. Thus, aspects disclosed herein providetechniques for performing DMRS bundling over a first slot and a secondslot that are a threshold quantity of slots apart (e.g., n slots in theexample of FIG. 6 ) and using a first symbol of the first slot and asecond symbol of the second slot that are associated with a similar CPEto estimate the phase jump.

FIG. 10 illustrates an example 1000 of phase jump estimation using anAGC symbol, as presented herein. In the illustrated example of FIG. 10 ,a first slot 1010 and a second slot 1020 are separated by less than athreshold quantity of slots. For example, the first slot 1010 and thesecond slot 1020 may be back-to-back slots (e.g., n=0 between the slots1010, 1020). As shown in FIG. 10 , the first slot 1010 and the secondslot 1020 include an AGC symbol 1012, 1022, respectively, that eachinclude AGC. The AGC symbols 1012, 1022 facilitate a receiving device toadjust the gain of the receiver amplifier to fit the total power of thereceived signal for the slot. The total power of the received signal mayinclude the power associated with the transmission and interference(e.g., due to neighboring devices).

In the illustrated example of FIG. 10 , an AGC setting of a first AGCsymbol 1012 and an AGC setting of a second AGC symbol 1022 may be a sameAGC setting, such as a same low noise amplifier (LNA) gain. However, thecontent of the second AGC symbol 1022 may be different than the contentof the first AGC symbol 1012. For example, in the example of FIG. 10 ,the second AGC symbol 1022 may include a copy of a last PSSCH symbol1014 of the first slot 1010. That is, the second AGC symbol 1022 may bea repetition of the last PSSCH symbol 1014. In such examples, the lastPSSCH symbol 1014 and the second AGC symbol 1022 may be used to estimatethe phase jump in the second slot 1020. For example, the last PSSCHsymbol 1014 may be associated with a first phase error 1016 and thesecond AGC symbol 1022 may be associated with a second phase error 1024.Similar to the example of FIG. 9B, the first phase error 1016 mayinclude a first CPE (“CPE1”) and the second phase error 1024 may includea second CPE (“CPE2”) and a phase jump 1026.

In some examples, when the first slot 1010 and the second slot 1020 areseparated by less than a threshold quantity of slots, the first CPE ofthe last PSSCH symbol 1014 and the second CPE of the second AGC symbol1022 may be similar. In such examples, the receiving device may useEquation 7 (above) to estimate the phase jump 1026. The receiving devicemay then use the estimate of the phase jump 1026 to remove it from thesignal received in the DMRS symbols of the second slot 1020 and togenerate a copy of the signal received in the DMRS symbols of the firstslot 1010. The receiving device may use the signal received in the DMRSsymbols of the first slot 1010 and the copy of the signal to performjoint channel estimation, such as DMRS bundling, as described inconnection with the example second scenario 720 of FIG. 7C.

FIG. 11 illustrates an example 1100 of phase jump estimation using alast PSSCH symbol of a preceding slot, as presented herein. Similar tothe example of FIG. 10 , in the illustrated example of FIG. 11 , a firstslot 1110 and a second slot 1120 are separated by less than a thresholdquantity of slots. For example, the first slot 1110 and the second slot1120 may be back-to-back slots (e.g., n=0 between the slots 1110, 1120).In the illustrated example of FIG. 11 , a portion of a symbol of thefirst slot 1110 may be repeated in a portion of a symbol of the secondslot 1120. In such examples, the portion of the symbol of the secondslot 1120 may be used to estimate the phase jump from the first slot1110 to the second slot 1120.

For example, in the illustrated example of FIG. 11 , a last PSSCH symbol1112 (e.g., symbol 13) of the first slot 1110 is a PSSCH symbol. In suchexamples, a portion 1114 of the last PSSCH symbol 1112 may be repeatedin a PSSCH portion of a symbol of the second slot 1120. For example, theportion 1114 may be repeated in a PSSCH portion 1124 of a first non-AGCsymbol 1122 (e.g., a symbol 2) of the second slot 1120. In someexamples, the first non-AGC symbol 1122 may be referred to as a firstOFDM symbol. Similar to the example of FIG. 10 , the last PSSCH symbol1112 may be associated with a first phase error 1116 and the firstnon-AGC symbol 1122 may be associated with a second phase error 1126.Similar to the example of FIG. 10 , the first phase error 1116 mayinclude a first CPE (“CPE1”) and the second phase error 1126 may includea second CPE (“CPE2”) and a phase jump 1128.

In some examples, when the first slot 1110 and the second slot 1120 areseparated by less than a threshold quantity of slots, the first CPE ofthe last PSSCH symbol 1112 of the first slot 1110 and the second CPE ofthe first non-AGC symbol 1122 of the second slot 1120 may be similar. Insuch examples, the receiving device may use Equation 7 (above) toestimate the phase jump 1128. The receiving device may then use theestimate of the phase jump 1128 to remove it from the signal received atevery non-AGC symbol in the second slot 1120, including symbolscontaining DMRS, and to generate a copy of the DMRS signal received inthe DMRS symbols of the first slot 1110. The receiving device may usethe DMRS signal received in DMRS symbols in the first slot 1110 and thecopy of the DMRS signal to perform joint channel estimation, such asDMRS bundling, as described in connection with the example secondscenario 720 of FIG. 7C.

FIG. 12 illustrates an example 1200 of phase jump estimation using PSCCHDMRS, as presented herein. Similar to the example of FIGS. 10 and 11 ,in the illustrated example of FIG. 12 , a first slot 1210 and a secondslot 1220 are separated by less than a threshold quantity of slots. Forexample, the first slot 1210 and the second slot 1220 may beback-to-back slots (e.g., n=0 between the slots 1210, 1220). In theillustrated example of FIG. 12 , a portion of a symbol of the secondslot 1220 may be a repetition of a portion of a symbol of the first slot1210. In such examples, the portion of the symbol of the second slot1220 may be used to estimate the phase jump from the first slot 1210 tothe second slot 1220.

For example, in the illustrated example of FIG. 12 , a portion 1214 of alast PSSCH symbol 1212 of the first slot 1210 may be repeated in a PSCCHportion 1224 of a first non-AGC symbol 1222 of the second slot 1220. Forexample, the portion 1214 may be repeated in the PSCCH portion 1224 ofthe first non-AGC symbol 1222 (e.g., a symbol 2) of the second slot1220. As shown in FIG. 12 , the PSCCH portion 1224 may include a DMRSpattern 1230. A transmitting device may include the DMRS pattern 1230 inthe portion 1214 so that the PSCCH portion 1224 is a repeat of theportion 1214. Similar to the examples of FIGS. 10 and 11 , the lastPSSCH symbol 1212 may be associated with a first phase error 1216 andthe first non-AGC symbol 1222 may be associated with a second phaseerror 1226. Similar to the examples of FIGS. 10 and 11 , the first phaseerror 1216 may include a first CPE (“CPE1”) and the second phase error1226 may include a second CPE (“CPE2”) and a phase jump 1228.

In some examples, when the first slot 1210 and the second slot 1220 areseparated by less than a threshold quantity of slots, the first CPE ofthe last PSSCH symbol 1212 of the first slot 1210 and the second CPE ofthe first non-AGC symbol 1222 of the second slot 1220 may be similar. Insuch examples, the receiving device may use Equation 7 (above) toestimate the phase jump 1228. The receiving device may then use theestimate of the phase jump 1228 to remove it from the signal received atevery non-AGC symbol of the second slot 1220, including symbolscontaining DMRS, and to generate a copy of the DMRS signal received inthe DMRS symbols of the first slot 1210. The receiving device may usethe DMRS signal received in the DMRS symbols in the first slot 1210 andthe copy of the DMRS signal to perform joint channel estimation, such asDMRS bundling, as described in connection with the example secondscenario 720 of FIG. 7C.

FIG. 13 illustrates another example 1300 of phase jump estimation usingPSCCH DMRS, as presented herein. Similar to the example of FIGS. 10, 11,and 12 , in the illustrated example of FIG. 13 , a first slot 1310 and asecond slot 1320 are separated by less than a threshold quantity ofslots. For example, the first slot 1310 and the second slot 1320 may beback-to-back slots (e.g., n=0 between the slots 1310, 1320).

In the illustrated example of FIG. 13 , the first slot 1310 includes aguard symbol 1312 that includes a gap. The guard symbol 1312 provides aswitching time to allow a receiving device to facilitate switchingbetween sidelink transmission/reception (and vice versa), and tofacilitate switching between sidelink and downlink/uplink transmissions(and vice versa). For example, a receiving device may use a first beamto receive the first slot 1310 and use the guard symbol 1312 to switchto a second beam to transmit the second slot 1320.

However, in scenarios in which there is no switch from a first beam to asecond beam, providing a switching time may be avoided. That is, theguard symbol 1312 may be used to include information. In the illustratedexample of FIG. 13 , a portion of a symbol of the second slot 1320 maybe a repetition of a portion of a symbol of the first slot 1310. In suchexamples, the portion of the symbol of the second slot 1320 may be usedto estimate the phase jump from the first slot 1310 to the second slot1320.

For example, in the illustrated example of FIG. 13 , the guard symbol1312 may include a portion of a first non-AGC symbol 1322 of the secondslot 1320. In the illustrated example, a PSCCH portion 1324 of the firstnon-AGC symbol 1322 (e.g., symbol 2) is also transmitted in a portion1314 of the guard symbol 1312. Similar to the example of FIG. 12 , thePSCCH portion 1324 of FIG. 13 may include a DMRS pattern 1330. Atransmitting device may include the DMRS pattern 1330 in the portion1314 of the guard symbol 1312 so that the PSCCH portion 1324 is arepetition of the portion 1314. Similar to the examples of FIGS. 10, 11,and 12 , the guard symbol 1312 may be associated with a first phaseerror 1316 and the first non-AGC symbol 1322 may be associated with asecond phase error 1326. Similar to the examples of FIGS. 10, 11, and 12, the first phase error 1316 may include a first CPE (“CPE1”) and thesecond phase error 1326 may include a second CPE (“CPE2”) and a phasejump 1328.

In some examples, when the first slot 1310 and the second slot 1320 areseparated by less than a threshold quantity of slots, the first CPE ofthe guard symbol 1312 of the first slot 1310 and the second CPE of thefirst non-AGC symbol 1322 of the second slot 1320 may be similar. Insuch examples, the receiving device may use Equation 7 (above) toestimate the phase jump 1328. The receiving device may then use theestimate of the phase jump 1328 to remove it from the signal in thesecond slot 1320 and to generate a copy of the DMRS signal received inthe first slot 1310. The receiving device may use the DMRS signalreceived in the first slot 1310 and the copy of the DMRS signal toperform joint channel estimation, such as DMRS bundling, as described inconnection with the example second scenario 720 of FIG. 7C.

FIG. 14 illustrates an example communication flow 1400 between a firstwireless device 1402 and a second wireless device 1404, as presentedherein. In the illustrated example, the communication flow 1400facilitates the first wireless device 1402 to perform phase jumpestimation to facilitate DMRS bundling. Aspects of the first wirelessdevice 1402 and the second wireless device 1404 may be implemented bythe UE 104 of FIG. 1 , the first wireless communication device 310 ofFIG. 3 , and/or the second wireless communication device 350 of FIG. 3 .Although not shown in the illustrated example of FIG. 14 , in additionalor alternative examples, the first wireless device 1402 may be incommunication with one or more other base stations or UEs, and/or thesecond wireless device 1404 may be in communication with one or moreother base stations or UEs.

In some examples, the first wireless device 1402 and the second wirelessdevice 1404 may include UEs with the capability to support sidelinkcommunication. For example, the first wireless device 1402 may include afirst sidelink device and the second wireless device 1404 may include asecond sidelink device. In some examples, one of the first wirelessdevice 1402 and the second wireless device 1404 may include a basestation and the other of the first wireless device 1402 and the secondwireless device 1404 may include a UE. For example, the first wirelessdevice 1402 may include a base station, the second wireless device 1404may include a UE, and communication from the second wireless device 1404to the first wireless device 1402 may include an uplink transmission. Inother examples, the first wireless device 1402 may include a UE, thesecond wireless device 1404 may include a base station, andcommunication from the second wireless device 1404 to the first wirelessdevice 1402 may include a downlink transmission.

In the illustrated example of FIG. 14 , the first wireless device 1402is a receiving UE that receives transport block(s) from the secondwireless device 1404 (e.g. a transmitting UE). For example, the secondwireless device 1404 may transmit a first slot 1420 and a second slot1422 that are received by the first wireless device 1402. The first slot1420 and the second slot 1422 may be part of a same transmission fromthe second wireless device 1404 to the first wireless device 1402. Thefirst slot 1420 and the second slot 1422 may be included in a sidelinkDMRS bundling window, such as the example sidelink DMRS bundling window600 of FIG. 6 . For example, the first slot 1420 and the second slot1422 may be separated by n slots. In some examples, the first slot 1420and the second slot 1422 may be consecutive slots (e.g., n=0 slots).

Aspects of the first slot 1420 may be implemented by the first slot 610of FIG. 6 , the first slot 702 of FIGS. 7A, 7B, and 7C, the first slot960 of FIG. 9B, the first slot 1010 of FIG. 10 , the first slot 1110 ofFIG. 11 , the first slot 1210 of FIG. 12 , and/or the first slot 1310 ofFIG. 13 . Aspects of the second slot 1422 may be implemented by thesecond slot 620 of FIG. 6 , the second slot 704 of FIGS. 7A, 7B, and 7C,the second slot 970 of FIG. 9B, the second slot 1020 of FIG. 10 , thesecond slot 1120 of FIG. 11 , the second slot 1220 of FIG. 12 , and/orthe second slot 1320 of FIG. 13 .

At 1430, the first wireless device 1402 measures a first phase error fora symbol of the first slot 1420. At 1432, the first wireless device 1402measures a second phase error for a symbol of the second slot 1422. Thefirst phase error and the second phase error may include a respectivecommon phase error (CPE) that is applied to each tone of a symbol. Forexample, the CPE of a symbol may cause the tones of the symbol to rotatewith respective to a constellation. In some examples, the rotation ofthe tones may cause stretching and/or shrinking of the points to aconstellation, as described in connection with FIG. 8 .

While the CPE is time-varying, the CPE is also relatively slowlytime-varying. For example, the CPE of a first symbol may be similar tothe CPE of a second symbol that is adjacent to the first symbol.Accordingly, when the first slot 1420 and the second slot 1422 are lessthan a threshold quantity of slots apart, the symbol associated with thefirst phase error (e.g., at 1430) and the symbol associated with thesecond phase error (e.g., at 1432) may have similar CPE values. In suchexamples, the difference between the second phase error and the firstphase error may correspond to a phase jump between the first slot 1420and the second slot 1422.

At 1440, the first wireless device 1402 may estimate a phase jump basedon the first phase error and the second phase error. For example, thefirst wireless device 1402 may apply Equation 7 (reproduced below) toestimate the phase jump.

$\begin{matrix}{\frac{e^{j \star {cPE}_{1}}*A}{e^{j \star {CPE}_{2}}*e^{j \star {{phase}\_{jump}}}*A} = e^{{- j}*{{phase}\_{jump}}}} & {{Equation}7}\end{matrix}$

At 1442, the first wireless device 1402 may generate a copy of a signalof the symbol of the first slot 1420 based on the estimated phase jumpand a signal of the symbol of the second slot 1422. For example, andreferring to the example of FIG. 7C, the first wireless device 1402 maymodify the second slot DMRS signal 724 based on the phase jump 726 togenerate the generated DMRS signal 728 that is a copy of the first slotDMRS signal 722.

In some examples, the first wireless device 1402 may generate a signalthat is a copy of the signal of the symbol of the first slot 1420 basedon modifying the phases of the respective signals. For example, thefirst wireless device 1402 may modify the second phase error associatedwith the symbol of the second slot 1422 based on the phase jump. Asdescribed above, the information of the symbol of the second slot 1422and the information of the symbol of the first slot 1420 are copies. Asa result, the signals at the respective symbols are expected to becopies, as described in connection with the example first scenario 710of FIG. 7B. However, due to the phase jump between the first slot 1420and the second slot 1422, the signal of the second slot 1422 may beoffset from the signal of the first slot 1420 by the value of the phasejump. Thus, the first wireless device 1402 may modify the signal of thesecond slot 1422 based on the phase jump to reproduce the signal of thefirst slot 1420.

At 1444, the second wireless device 1444 may perform joint channelestimation, such as DMRS bundling. For example, the second wirelessdevice 1444 may perform coherent combining of the DMRS signal of thesymbol of the first slot 1420 and the generated copy of the DMRS signal.Combining the signal across the first slot 1420 and the second slot 1422may improve the channel condition estimation. By accurately estimatingchannel conditions, a higher MCS may be selected for transmissions,which may increase throughput.

Although the above example of FIG. 14 describes using phase jumpestimation to perform DMRS bundling, it may be appreciated that in otherexamples, the phase jump estimation may be used to perform additional oralternative joint channel estimations.

In some examples, at least a portion of the symbol of the first slot1420 and a portion of the symbol of the second slot 1422 may be copies.For example, in a first scenario, the second wireless device 1404 mayrepeat the last data symbol of the first slot 1420 in an AGC symbol ofthe second slot 1422. For example, and referring to the example of FIG.10 , a transmitting device may copy the last PSSCH symbol 1014 of thefirst slot 1010 into the second AGC symbol 1022 of the second slot 1020.In some such examples, the CPE associated with the last PSSCH symbol1014 and the second AGC symbol 1022 may be similar. The first wirelessdevice 1402 may then use the difference in phase error of the last PSSCHsymbol 1014 and the second AGC symbol 1022 may be used to estimate thephase jump (e.g., at 1440).

In an example second scenario, the second wireless device 1404 mayrepeat a portion of the last data symbol of the first slot 1420 in aportion of a symbol of the second slot 1422. For example, and referringto the example of FIG. 11 , a transmitting device may copy the portion1114 of the last PSSCH symbol 1112 of the first slot 1110 into the PSSCHportion 1124 of the first non-AGC symbol 1122 of the second slot 1120.In some such examples, the CPE associated with the portion 1114 and thePSSCH portion 1124 may be similar. The first wireless device 1402 maythen use the difference in phase error of the portion 1114 and the PSSCHportion 1124 may be used to estimate the phase jump (e.g., at 1440).

In an example third scenario, the second wireless device 1404 may repeata portion of control information of a symbol of the second slot 1422 ina portion of the last data symbol of the first slot 1420 so that thecontrol information of the symbol of the second slot 1422 is arepetition of the portion of the last data symbol of the first slot1420. For example, and referring to the example of FIG. 12 , atransmitting device may copy the PSCCH portion 1224 of the first non-AGCsymbol 1222 of the second slot 1220 into the portion 1214 of the lastPSSCH symbol 1212 before transmitting the first slot 1210. In some suchexamples, the CPE associated with the portion 1214 and the PSCCH portion1224 may be similar. The first wireless device 1402 may then use thedifference in phase error of the portion 1214 and the PSCCH portion 1224to estimate the phase jump (e.g., at 1440).

In an example fourth scenario, the second wireless device 1404 mayrepeat control information of a symbol of the second slot 1422 in aguard symbol of the first slot 1420. For example, and referring to theexample of FIG. 13 , a transmitting device may copy the PSCCH portion1324 of the first non-AGC symbol 1322 into the portion 1314 of the guardsymbol 1312 of the first slot 1310. In some such examples, the CPEassociated with the portion 1314 and the PSCCH portion 1324 may besimilar. The first wireless device 1402 may then use the difference inphase error of the portion 1314 and the PSCCH portion 1324 to estimatethe phase jump (e.g., at 1440).

In some examples, the second wireless device 1404 may configure thefirst wireless device 1402 with a bundling pattern to facilitate thefirst wireless device 1402 to determine which symbols of the first slot1420 and the second slot 1422 to use to estimate the phase jump. Forexample, at 1410, the second wireless device 1404 may configure abundling pattern by determining which portion of a symbol of the firstslot 1420 to repeat in a portion of a symbol of the second slot 1422.For example, in the example first scenario of FIG. 10 , the secondwireless device 1404 may determine to copy the last PSSCH symbol of thefirst slot into the AGC symbol of the second slot. In the example secondscenario of FIG. 11 , the second wireless device 1404 may determine tocopy a portion of the last PSSCH symbol of the first slot into a PSSCHportion of the first non-AGC symbol of the second slot. In the examplethird scenario of FIG. 12 , the second wireless device 1404 maydetermine to copy control information of the first non-AGC symbol of thesecond slot into a portion of the last PSSCH symbol of the first slot.In the example fourth scenario, the second wireless device 1404 maydetermine to copy control information of the first non-AGC symbol of thesecond slot into a portion of the guard symbol of the first slot.

The second wireless device 1404 may then transmit a configuration 1412that is received by the first wireless device 1402. The configuration1412 may indicate the symbols that the first wireless device 1402 is touse to estimate the phase jump. At 1414, the first wireless device 1402may configure the bundling pattern based on the configuration 1412. Forexample, the first wireless device 1402 may be configured to assume thatthe same precoder is used by the second wireless device 1404 across thedata channels of the first slot 1420 and the second slot 1422. Thesecond wireless device 1404 may transmit the first slot 1420 and thesecond slot 1422 based on the determined bundling pattern (e.g., at1410).

FIG. 15 is a flowchart 1500 of a method of wireless communication. Themethod may be performed by a first wireless device (e.g., the UE 104,the second wireless communication device 350, and/or an apparatus 1702of FIG. 17 ). The method may facilitate improving throughput by enablingthe first wireless device to improve channel estimation and tocommunicate with a second wireless device using a high MCS.

In some examples, the first wireless device may include a first sidelinkdevice and the second wireless device may include a second sidelinkdevice. In some examples, the first wireless device may include a basestation and the second wireless device may include a UE. In someexamples, the first wireless device may include a UE and the secondwireless device may include a base station.

At 1502, the first wireless device receives, from a second wirelessdevice, first information at a first symbol of a first slot, asdescribed in connection with the first slot 1420 of FIG. 14 . The firstslot may include at least the first symbol and a first reference signal.The receiving of the first slot, at 1502, may be performed by a firstslot component 1740 of the apparatus 1702 of FIG. 17 .

At 1504, the first wireless device receives second information at asecond symbol of a second slot, as described in connection with thesecond slot 1422 of FIG. 14 . The second slot may include at least thesecond symbol and a second reference signal. The first information andthe second information may be copies. The receiving of the second slot,at 1504, may be performed by a second slot component 1742 of theapparatus 1702 of FIG. 17 .

At 1506, the first wireless device generates a first reference signalcopy based at least on the second reference signal and a phase jump, asdescribed in connection with 1442 of FIG. 14 . For example, the firstwireless device may modify a phase of the second reference signal basedon the phase jump to generate the first reference signal copy, asdescribed in connection with the example second scenario 720 of FIG. 7C.The phase jump may be based on a first phase error associated with thefirst symbol and a second phase error associated with the second symbol.The generating of the first reference signal copy, at 1506, may beperformed by a signal component 1746 of the apparatus 1702 of FIG. 17 .

At 1508, the first wireless device performs channel estimation acrossthe first slot and the second slot based on an aggregation of the firstreference signal and the first reference signal copy, as described inconnection with 1444 of FIG. 14 . In some examples, the first wirelessdevice may perform channel estimation based on an aggregation of thefirst reference signal and the first reference signal copy. Theperforming of the DMRS bundling, at 1508, may be performed by a channelestimation component 1748 of the apparatus 1702 of FIG. 17 .

In some examples, the second information may be a copy of the firstinformation. For example, in the example first scenario of FIG. 10 , thefirst symbol of the first slot may include a last data symbol (e.g., thelast PSSCH symbol 1014) and the second symbol of the second slot mayinclude an AGC symbol (e.g., the second AGC symbol 1022). In suchexamples, the second information of the second slot may be a copy of thefirst information of the first slot.

In some examples, the first information and the second information mayinclude portions of the respective symbols. For example, in the examplesecond scenario of FIG. 11 , the first symbol of the first slot includesa last data symbol (e.g., the last PSSCH symbol 1112) and the secondsymbol of the second slot includes a first non-AGC symbol (e.g., thefirst non-AGC symbol 1122). In such examples, the second information mayinclude a data portion of the second symbol (e.g., the PSSCH portion1124), the first information may include a portion of the first symbol(e.g., the portion 1114), and the second information may be a copy ofthe first information.

In an example third scenario of FIG. 12 , the first symbol of the firstslot may include a last data symbol (e.g., the last PSSCH symbol 1212)and the second symbol of the second slot may include a first non-AGCsymbol (e.g., the first non-AGC symbol 1222). In such examples, thesecond information may include a control portion of the second symbol(e.g., the PSCCH portion 1224), the first information may include aportion of the first symbol (e.g., portion 1214), and the firstinformation may be a copy of the second information.

In an example fourth scenario of FIG. 13 , the first symbol of the firstslot may include a guard symbol (e.g., the guard symbol 1312) and thesecond symbol of the second slot may include a first non-AGC symbol(e.g., first non-AGC symbol 1322). In such examples, the secondinformation may include a control portion of the second symbol (e.g.,the PSCCH portion 1324), the first information may include a portion ofthe first symbol (e.g., the portion 1314), and the first information maybe a copy of the second information.

FIG. 16 is a flowchart 1600 of a method of wireless communication. Themethod may be performed by a first wireless device (e.g., the UE 104,the second wireless communication device 350, and/or an apparatus 1702of FIG. 17 ). The method may facilitate improving throughput by enablingthe first wireless device to improve channel estimation and tocommunicate with a second wireless device using a high MCS.

In some examples, the first wireless device may include a first sidelinkdevice and the second wireless device may include a second sidelinkdevice. In some examples, the first wireless device may include a basestation and the second wireless device may include a UE. In someexamples, the first wireless device may include a UE and the secondwireless device may include a base station.

At 1604, the first wireless device receives, from a second wirelessdevice, first information at a first symbol of a first slot, asdescribed in connection with the first slot 1420 of FIG. 14 . The firstslot may include at least the first symbol and a first reference signal.The receiving of the first slot, at 1604, may be performed by a firstslot component 1740 of the apparatus 1702 of FIG. 17 .

At 1606, the first wireless device receives second information at asecond symbol of a second slot, as described in connection with thesecond slot 1422 of FIG. 14 . The second slot may include at least thesecond symbol and a second reference signal. The first information andthe second information may be copies. The receiving of the second slot,at 1606, may be performed by a second slot component 1742 of theapparatus 1702 of FIG. 17 .

In some examples, the first slot and the second slot may be separated bya threshold quantity of slots. For example, the first slot and thesecond slot may be included in a bundling window, such as the examplesidelink DMRS bundling window 600 of FIG. 6 . In some examples, thethreshold quantity of slots may be zero. In such examples, the firstslot and the second slot may be consecutive slots. In some examples, thethreshold quantity of slots may be greater than zero. In such examples,the first slot and the second slot may be non-consecutive slots.

At 1608, the first wireless device may estimate a phase jump between thefirst slot and the second slot, as described in connection with 1440 ofFIG. 14 . In some examples, a first CPE associated with the first slotand a second CPE associated with the second slot may be similar. Forexample, a last data symbol of the first slot may be associated with afirst CPE, a first symbol of the second slot may be associated with asecond CPE, and a difference between the first CPE and the second CPEmay be less than a threshold. In such examples, the first wirelessdevice may estimate the phase jump based on a difference between a firstphase error associated with the first symbol of the first slot and asecond phase error associated with the second symbol of the second slot.The estimating of the phase jump, at 1608, may be performed by a phasejump component 1744 of the apparatus 1702 of FIG. 17 .

At 1610, the first wireless device generates a first reference signalcopy based at least on the second reference signal and the phase jump,as described in connection with 1442 of FIG. 14 . For example, the firstwireless device may modify a phase of the second reference signal basedon the phase jump to generate the first reference signal copy, asdescribed in connection with the example second scenario 720 of FIG. 7C.The phase jump may be based on a first phase error associated with thefirst symbol and a second phase error associated with the second symbol.The generating of the first reference signal copy, at 1610, may beperformed by a signal component 1746 of the apparatus 1702 of FIG. 17 .

At 1612, the first wireless device performs channel estimation acrossthe first slot and the second slot based on an aggregation of the firstreference signal and the first reference signal copy, as described inconnection with 1444 of FIG. 14 . In some examples, the first wirelessdevice may perform channel estimation based on an aggregation of thefirst reference signal and the first reference signal copy. Theperforming of the DMRS bundling, at 1612, may be performed by a channelestimation component 1748 of the apparatus 1702 of FIG. 17 .

In some examples, the first wireless device may be configured todetermine the symbols to combine to use for the channel estimation. Forexample, at 1602, the first wireless device may receive a configurationfor a bundling pattern, as described in connection with theconfiguration 1412 of FIG. 14 . The configuration may include a patternindicating the first symbol of the first slot and the second symbol ofthe second slot. The receiving of the configuration, at 1602, may beperformed by a configuration component 1750 of the apparatus 1702 ofFIG. 17 .

In some examples, the second information may be a copy of the firstinformation. For example, in the example first scenario of FIG. 10 , thefirst symbol of the first slot may include a last data symbol (e.g., thelast PSSCH symbol 1014) and the second symbol of the second slot mayinclude an AGC symbol (e.g., the second AGC symbol 1022). In suchexamples, the second information of the second slot may be a copy of thefirst information of the first slot.

In some examples, the first information and the second information mayinclude portions of the respective symbols. For example, in the examplesecond scenario of FIG. 11 , the first symbol of the first slot includesa last data symbol (e.g., the last PSSCH symbol 1112) and the secondsymbol of the second slot includes a first non-AGC symbol (e.g., thefirst non-AGC symbol 1122). In such examples, the second information mayinclude a data portion of the second symbol (e.g., the PSSCH portion1124), the first information may include a portion of the first symbol(e.g., the portion 1114), and the second information may be a copy ofthe first information.

In an example third scenario of FIG. 12 , the first symbol of the firstslot may include a last data symbol (e.g., the last PSSCH symbol 1212)and the second symbol of the second slot may include a first non-AGCsymbol (e.g., the first non-AGC symbol 1222). In such examples, thesecond information may include a control portion of the second symbol(e.g., the PSCCH portion 1224), the first information may include aportion of the first symbol (e.g., portion 1214), and the firstinformation may be a copy of the second information.

In an example fourth scenario of FIG. 13 , the first symbol of the firstslot may include a guard symbol (e.g., the guard symbol 1312) and thesecond symbol of the second slot may include a first non-AGC symbol(e.g., first non-AGC symbol 1322). In such examples, the secondinformation may include a control portion of the second symbol (e.g.,the PSCCH portion 1324), the first information may include a portion ofthe first symbol (e.g., the portion 1314), and the first information maybe a copy of the second information.

FIG. 17 is a diagram 1700 illustrating an example of a hardwareimplementation for an apparatus 1702. The apparatus 1702 may be a UE, oranother device configured to transmit and/or receive sidelinkcommunication. The apparatus 1702 includes a baseband processor 1704(also referred to as a modem) coupled to a RF transceiver 1722. In someaspects, the baseband processor 1704 may be a cellular basebandprocessor and/or the RF transceiver 1722 may be a cellular RFtransceiver. The apparatus 1702 may further include one or moresubscriber identity modules (SIM) cards 1720, an application processor1706 coupled to a secure digital (SD) card 1708 and a screen 1710, aBluetooth module 1712, a wireless local area network (WLAN) module 1714,a Global Positioning System (GPS) module 1716, and/or a power supply1718. The baseband processor 1704 communicates through the RFtransceiver 1722 with the UE 104 and/or the base station 102/180. Thebaseband processor 1704 may include a computer-readable medium/memory.The computer-readable medium/memory may be non-transitory. The basebandprocessor 1704 is responsible for general processing, including theexecution of software stored on the computer-readable medium/memory. Thesoftware, when executed by the baseband processor 1704, causes thebaseband processor 1704 to perform the various functions described inthe present application. The computer-readable medium/memory may also beused for storing data that is manipulated by the baseband processor 1704when executing software. The baseband processor 1704 further includes areception component 1730, a communication manager 1732, and atransmission component 1734. The communication manager 1732 includes theone or more illustrated components. The components within thecommunication manager 1732 may be stored in the computer-readablemedium/memory and/or configured as hardware within the basebandprocessor 1704. The baseband processor 1704 may be a component of thesecond wireless communication device 350 and may include the memory 360and/or at least one of the TX processor 368, the RX processor 356, andthe controller/processor 359. In one configuration, the apparatus 1702may be a modem chip and include just the baseband processor 1704, and inanother configuration, the apparatus 1702 may be the entire UE (e.g.,see the second wireless communication device 350 of FIG. 3 ) and includethe additional modules of the apparatus 1702.

The communication manager 1732 includes a first slot component 1740 thatis configured to receive, from a second wireless device, firstinformation at a first symbol of a first slot, the first slot includingat least the first symbol and a first reference signal, for example, asdescribed in connection with 1502 of FIGS. 15 and/or 1604 of FIG. 16 .

The communication manager 1732 also includes a second slot component1742 that is configured to receive second information at a second symbolof a second slot, the second slot including at least the second symboland a second reference signal, the first information and the secondinformation being repetitions, for example, as described in connectionwith 1504 of FIGS. 15 and/or 1606 of FIG. 16 .

The communication manager 1732 also includes a phase jump component 1744that is configured to estimate a phase jump between the first slot andthe second slot, for example, as described in connection with 1608 ofFIG. 16 .

The communication manager 1732 also includes a signal component 1746that is configured to generate a first reference signal copy based atleast on the second reference signal and a phase jump between the firstslot and the second slot, the phase jump based on a first phase errorassociated with the first symbol and a second phase error associatedwith the second symbol, for example, as described in connection with1506 of FIGS. 15 and/or 1610 of FIG. 16 .

The communication manager 1732 also includes a channel estimationcomponent 1748 that is configured to perform channel estimation acrossthe first slot and the second slot based on an aggregation of the firstreference signal and the first reference signal copy, for example, asdescribed in connection with 1508 of FIGS. 15 and/or 1612 of FIG. 16 .

The communication manager 1732 also includes a configuration component1750 that is configured to receive a configuration for a bundlingpattern, for example, as described in connection with 1602 of FIG. 16 .

The apparatus may include additional components that perform each of theblocks of the algorithm in the flowcharts of FIGS. 15 and/or 16 . Assuch, each block in the flowcharts of FIGS. 15 and/or 16 may beperformed by a component and the apparatus may include one or more ofthose components. The components may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

As shown, the apparatus 1702 may include a variety of componentsconfigured for various functions. In one configuration, the apparatus1702, and in particular the baseband processor 1704, includes means forreceiving, from a second wireless device, first information at a firstsymbol of a first slot, the first slot including at least the firstsymbol and a first reference signal. The example apparatus 1702 alsoincludes means for receiving second information at a second symbol of asecond slot, the second slot including at least the second symbol and asecond reference signal, the first information and the secondinformation being repetitions. The example apparatus 1702 also includesmeans for generating a first reference signal copy based at least on thesecond reference signal and a phase jump between the first slot and thesecond slot, the phase jump based on a first phase error associated withthe first symbol and a second phase error associated with the secondsymbol. The example apparatus 1702 also includes means for performingchannel estimation across the first slot and the second slot based on anaggregation of the first reference signal and the first reference signalcopy.

The means may be one or more of the components of the apparatus 1702configured to perform the functions recited by the means. As describedsupra, the apparatus 1702 may include the TX processor 368, the RXprocessor 356, and the controller/processor 359. As such, in oneconfiguration, the means may be the TX processor 368, the RX processor356, and the controller/processor 359 configured to perform thefunctions recited by the means.

FIG. 18 is a flowchart 1800 of a method of wireless communication with afirst wireless device. The method may be performed by a second wirelessdevice (e.g., the UE 104, the first wireless communication device 310,and/or an apparatus 2002 of FIG. 20 ). The method may facilitateimproving throughput by enabling the first wireless device to improvechannel estimation and to communicate with the second wireless deviceusing a high MCS.

In some examples, the first wireless device may include a first sidelinkdevice and the second wireless device may include a second sidelinkdevice. In some examples, the first wireless device may include a basestation and the second wireless device may include a UE. In someexamples, the first wireless device may include a UE and the secondwireless device may include a base station.

At 1802, the second wireless device transmits, to the first wirelessdevice, first information at a first symbol of a first slot, the firstslot including at least the first symbol and a first reference signal,as described in connection with the first slot 1420 of FIG. 14 . Thetransmitting of the first slot, at 1802, may be performed by a firstslot component 2040 of the apparatus 2002 of FIG. 20 .

At 1804, the second wireless device transmits second information at asecond symbol of a second slot, the second slot including at least thesecond symbol and a second reference signal, the first information andthe second information being repetitions, as described in connectionwith the second slot 1422 of FIG. 14 . The transmitting of the secondslot, at 1804, may be performed by a second slot component 2042 of theapparatus 2002 of FIG. 20 .

In some examples, the first slot and the second slot may be separated bya threshold quantity of slots. For example, the first slot and thesecond slot may be included in a bundling window, such as the examplesidelink DMRS bundling window 600 of FIG. 6 . In some examples, thethreshold quantity of slots may be zero. In such examples, the firstslot and the second slot may be consecutive slots. In some examples, thethreshold quantity of slots may be greater than zero. In such examples,the first slot and the second slot may be non-consecutive slots.

In some examples, a first CPE associated with the first slot and asecond CPE associated with the second slot may be similar. For example,a last data symbol of the first slot may be associated with a first CPE,a first symbol of the second slot may be associated with a second CPE,and a difference between the first CPE and the second CPE may be lessthan a threshold.

In some examples, the second information may be a copy of the firstinformation. For example, in the example first scenario of FIG. 10 , thefirst symbol of the first slot may include a last data symbol (e.g., thelast PSSCH symbol 1014) and the second symbol of the second slot mayinclude an AGC symbol (e.g., the second AGC symbol 1022). In suchexamples, the second information of the second slot may be a copy of thefirst information of the first slot.

In some examples, the first information and the second information mayinclude portions of the respective symbols. For example, in the examplesecond scenario of FIG. 11 , the first symbol of the first slot includesa last data symbol (e.g., the last PSSCH symbol 1112) and the secondsymbol of the second slot includes a first non-AGC symbol (e.g., thefirst non-AGC symbol 1122). In such examples, the second information mayinclude a data portion of the second symbol (e.g., the PSSCH portion1124), the first information may include a portion of the first symbol(e.g., the portion 1114), and the second information may be a copy ofthe first information.

In an example third scenario of FIG. 12 , the first symbol of the firstslot may include a last data symbol (e.g., the last PSSCH symbol 1212)and the second symbol of the second slot may include a first non-AGCsymbol (e.g., the first non-AGC symbol 1222). In such examples, thesecond information may include a control portion of the second symbol(e.g., the PSCCH portion 1224), the first information may include aportion of the first symbol (e.g., portion 1214), and the firstinformation may be a copy of the second information.

In an example fourth scenario of FIG. 13 , the first symbol of the firstslot may include a guard symbol (e.g., the guard symbol 1312) and thesecond symbol of the second slot may include a first non-AGC symbol(e.g., first non-AGC symbol 1322). In such examples, the secondinformation may include a control portion of the second symbol (e.g.,the PSCCH portion 1324), the first information may include a portion ofthe first symbol (e.g., the portion 1314), and the first information maybe a copy of the second information.

FIG. 19 is a flowchart 1900 of a method of wireless communication with afirst wireless device. The method may be performed by a second wirelessdevice (e.g., the UE 104, the first wireless communication device 310,and/or an apparatus 2002 of FIG. 20 ). The method may facilitateimproving throughput by enabling the first wireless device to improvechannel estimation and to communicate with the second wireless deviceusing a high MCS.

In some examples, the first wireless device may include a first sidelinkdevice and the second wireless device may include a second sidelinkdevice. In some examples, the first wireless device may include a basestation and the second wireless device may include a UE. In someexamples, the first wireless device may include a UE and the secondwireless device may include a base station.

At 1904, the second wireless device transmits, to the first wirelessdevice, first information at a first symbol of a first slot, the firstslot including at least the first symbol and a first reference signal,as described in connection with the first slot 1420 of FIG. 14 . Thetransmitting of the first slot, at 1904, may be performed by a firstslot component 2040 of the apparatus 2002 of FIG. 20 .

At 1906, the second wireless device transmits second information at asecond symbol of a second slot, the second slot including at least thesecond symbol and a second reference signal, the first information andthe second information being repetitions, as described in connectionwith the second slot 1422 of FIG. 14 . The transmitting of the secondslot, at 1906, may be performed by a second slot component 2042 of theapparatus 2002 of FIG. 20 .

In some examples, the first slot and the second slot may be separated bya threshold quantity of slots. For example, the first slot and thesecond slot may be included in a bundling window, such as the examplesidelink DMRS bundling window 600 of FIG. 6. In some examples, thethreshold quantity of slots may be zero. In such examples, the firstslot and the second slot may be consecutive slots. In some examples, thethreshold quantity of slots may be greater than zero. In such examples,the first slot and the second slot may be non-consecutive slots.

In some examples, a first CPE associated with the first slot and asecond CPE associated with the second slot may be similar. For example,a last data symbol of the first slot may be associated with a first CPE,a first symbol of the second slot may be associated with a second CPE,and a difference between the first CPE and the second CPE may be lessthan a threshold.

In some examples, the second wireless device may configure the firstwireless device to determine the symbols to combine to use for thechannel estimation. For example, at 1902, the second wireless device maytransmit a configuration indicating the first symbol and the secondsymbol, as described in connection with the configuration 1412 of FIG.14 . The configuration may include a pattern indicating the first symbolof the first slot and the second symbol of the second slot. Thetransmitting of the configuration, at 1902, may be performed by aconfiguration component 2044 of the apparatus 2002 of FIG. 20 .

In some examples, the second information may be a copy of the firstinformation. For example, in the example first scenario of FIG. 10 , thefirst symbol of the first slot may include a last data symbol (e.g., thelast PSSCH symbol 1014) and the second symbol of the second slot mayinclude an AGC symbol (e.g., the second AGC symbol 1022). In suchexamples, the second information of the second slot may be a copy of thefirst information of the first slot.

In some examples, the first information and the second information mayinclude portions of the respective symbols. For example, in the examplesecond scenario of FIG. 11 , the first symbol of the first slot includesa last data symbol (e.g., the last PSSCH symbol 1112) and the secondsymbol of the second slot includes a first non-AGC symbol (e.g., thefirst non-AGC symbol 1122). In such examples, the second information mayinclude a data portion of the second symbol (e.g., the PSSCH portion1124), the first information may include a portion of the first symbol(e.g., the portion 1114), and the second information may be a copy ofthe first information.

In an example third scenario of FIG. 12 , the first symbol of the firstslot may include a last data symbol (e.g., the last PSSCH symbol 1212)and the second symbol of the second slot may include a first non-AGCsymbol (e.g., the first non-AGC symbol 1222). In such examples, thesecond information may include a control portion of the second symbol(e.g., the PSCCH portion 1224), the first information may include aportion of the first symbol (e.g., portion 1214), and the firstinformation may be a copy of the second information.

In an example fourth scenario of FIG. 13 , the first symbol of the firstslot may include a guard symbol (e.g., the guard symbol 1312) and thesecond symbol of the second slot may include a first non-AGC symbol(e.g., first non-AGC symbol 1322). In such examples, the secondinformation may include a control portion of the second symbol (e.g.,the PSCCH portion 1324), the first information may include a portion ofthe first symbol (e.g., the portion 1314), and the first information maybe a copy of the second information.

FIG. 20 is a diagram 2000 illustrating an example of a hardwareimplementation for an apparatus 2002. The apparatus 2002 may be a UE, oranother device configured to transmit and/or receive sidelinkcommunication. The apparatus 2002 includes a baseband processor 2004(also referred to as a modem) coupled to a RF transceiver 2022. In someaspects, the baseband processor 2004 may be a cellular basebandprocessor and/or the RF transceiver 2022 may be a cellular RFtransceiver. The apparatus 2002 may further include one or moresubscriber identity modules (SIM) cards 2020, an application processor2006 coupled to a secure digital (SD) card 2008 and a screen 2010, aBluetooth module 2012, a wireless local area network (WLAN) module 2014,a Global Positioning System (GPS) module 2016, and/or a power supply2018. The baseband processor 2004 communicates through the RFtransceiver 2022 with the UE 104 and/or the base station 102/180. Thebaseband processor 2004 may include a computer-readable medium/memory.The computer-readable medium/memory may be non-transitory. The basebandprocessor 2004 is responsible for general processing, including theexecution of software stored on the computer-readable medium/memory. Thesoftware, when executed by the baseband processor 2004, causes thebaseband processor 2004 to perform the various functions described inthe present application. The computer-readable medium/memory may also beused for storing data that is manipulated by the baseband processor 2004when executing software. The baseband processor 2004 further includes areception component 2030, a communication manager 2032, and atransmission component 2034. The communication manager 2032 includes theone or more illustrated components. The components within thecommunication manager 2032 may be stored in the computer-readablemedium/memory and/or configured as hardware within the basebandprocessor 2004. The baseband processor 2004 may be a component of thefirst wireless communication device 310 and may include the memory 360and/or at least one of the TX processor 368, the RX processor 356, andthe controller/processor 359. In one configuration, the apparatus 2002may be a modem chip and include just the baseband processor 2004, and inanother configuration, the apparatus 2002 may be the entire UE (e.g.,see the first wireless communication device 310 of FIG. 3 ) and includethe additional modules of the apparatus 2002.

The communication manager 2032 includes a first slot component 2040 thatis configured to transmit, to the first wireless device, firstinformation at a first symbol of a first slot, the first slot includingat least the first symbol and a first reference signal, for example, asdescribed in connection with 1802 of FIGS. 18 and/or 1904 of FIG. 19 .

The communication manager 2032 also includes a second slot component2042 that is configured to transmit second information at a secondsymbol of a second slot, the second slot including at least the secondsymbol and a second reference signal, the first information and thesecond information being repetitions, for example, as described inconnection with 1804 of FIGS. 18 and/or 1906 of FIG. 19 .

The communication manager 2032 also includes a configuration component2044 that is configured to transmit a configuration indicating the firstsymbol and the second symbol, for example, as described in connectionwith 1902 of FIG. 19 .

The apparatus may include additional components that perform each of theblocks of the algorithm in the flowcharts of FIGS. 18 and/or 19 . Assuch, each block in the flowcharts of FIGS. 18 and/or 19 may beperformed by a component and the apparatus may include one or more ofthose components. The components may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

As shown, the apparatus 2002 may include a variety of componentsconfigured for various functions. In one configuration, the apparatus2002, and in particular the baseband processor 2004, includes means fortransmitting, to the first wireless device, first information at a firstsymbol of a first slot, the first slot including at least the firstsymbol and a first reference signal. The example apparatus 2002 alsoincludes means for transmitting second information at a second symbol ofa second slot, the second slot including at least the second symbol anda second reference signal, the first information and the secondinformation being repetitions.

In another configuration, the example apparatus 2002 also includes meansfor transmitting a configuration indicating the first symbol and thesecond symbol.

The means may be one or more of the components of the apparatus 2002configured to perform the functions recited by the means. As describedsupra, the apparatus 2002 may include the TX processor 368, the RXprocessor 356, and the controller/processor 359. As such, in oneconfiguration, the means may be the TX processor 368, the RX processor356, and the controller/processor 359 configured to perform thefunctions recited by the means.

The aspects presented herein may enable a first wireless device toestimate a phase jump between a first slot and a second slot, which mayfacilitate improving communication performance, for example, byimproving channel estimation and increasing throughput.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of example approaches.Based upon design preferences, it is understood that the specific orderor hierarchy of blocks in the processes/flowcharts may be rearranged.Further, some blocks may be combined or omitted. The accompanying methodclaims present elements of the various blocks in a sample order, and arenot meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Terms such as “if,” “when,” and“while” should be interpreted to mean “under the condition that” ratherthan imply an immediate temporal relationship or reaction. That is,these phrases, e.g., “when,” do not imply an immediate action inresponse to or during the occurrence of an action, but simply imply thatif a condition is met then an action will occur, but without requiring aspecific or immediate time constraint for the action to occur. The word“exemplary” is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects. Unless specifically stated otherwise, the term “some” refers toone or more. Combinations such as “at least one of A, B, or C,” “one ormore of A, B, or C,” “at least one of A, B, and C,” “one or more of A,B, and C,” and “A, B, C, or any combination thereof” include anycombination of A, B, and/or C, and may include multiples of A, multiplesof B, or multiples of C. Specifically, combinations such as “at leastone of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B,and C,” “one or more of A, B, and C,” and “A, B, C, or any combinationthereof” may be A only, B only, C only, A and B, A and C, B and C, or Aand B and C, where any such combinations may contain one or more memberor members of A, B, or C. All structural and functional equivalents tothe elements of the various aspects described throughout this disclosurethat are known or later come to be known to those of ordinary skill inthe art are expressly incorporated herein by reference and are intendedto be encompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. The words “module,”“mechanism,” “element,” “device,” and the like may not be a substitutefor the word “means.” As such, no claim element is to be construed as ameans plus function unless the element is expressly recited using thephrase “means for.”

The following aspects are illustrative only and may be combined withother aspects or teachings described herein, without limitation.

Aspect 1 is an apparatus for wireless communication at a first wirelessdevice including at least one processor coupled to a memory, the memoryand the at least one processor configured to receive, from a secondwireless device, first information at a first symbol of a first slot,the first slot including at least the first symbol and a first referencesignal; receive second information at a second symbol of a second slot,the second slot including at least the second symbol and a secondreference signal, the first information and the second information beingrepetitions; generate a first reference signal copy based at least onthe second reference signal and a phase jump between the first slot andthe second slot, the phase jump based on a first phase error associatedwith the first symbol and a second phase error associated with thesecond symbol; and perform channel estimation across the first slot andthe second slot based on an aggregation of the first reference signaland the first reference signal copy.

Aspect 2 is the apparatus of aspect 1, further including that the firstslot and the second slot are separated by a threshold quantity of slots.

Aspect 3 is the apparatus of any of aspects 1 and 2, further includingthat the first symbol of the first slot is associated with a first CPE,the second symbol of the second slot is associated with a second CPE,and a difference between the first CPE and the second CPE is less than athreshold.

Aspect 4 is the apparatus of any of aspects 1 to 2, further includingthat the first slot and the second slot are non-consecutive slots.

Aspect 5 is the apparatus of any of aspects 1 to 2, further includingthat the first slot and the second slot are consecutive slots.

Aspect 6 is the apparatus of any of aspects 1 to 5, further includingthat the phase jump is based on a difference between the second phaseerror and the first phase error.

Aspect 7 is the apparatus of any of aspects 1 to 6, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes an automatic gain controlsymbol, and the second information is a copy of the first information.

Aspect 8 is the apparatus of any of aspects 1 to 6, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the second information is a copy of the firstinformation, the second information including a data portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 9 is the apparatus of any of aspects 1 to 6, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the first information is a copy of the secondinformation, the second information including a control portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 10 is the apparatus of any of aspects 1 to 6, further includingthat the first symbol of the first slot includes a guard symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the first information is a copy of the secondinformation, the second information including a control portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 11 is the apparatus of any of aspects 1 to 10, further includingthat the first wireless device comprises a base station and the secondwireless device comprises a user equipment, or the first wireless devicecomprises the user equipment and the second wireless device comprisesthe base station.

Aspect 12 is the apparatus of any of aspects 1 to 10, further includingthat the first wireless device comprises a first sidelink device and thesecond wireless device comprises a second sidelink device.

Aspect 13 is the apparatus of any of aspects 1 to 12, further includinga transceiver coupled to the at least one processor.

Aspect 14 is a method of wireless communication for implementing any ofaspects 1 to 13.

Aspect 15 is an apparatus for wireless communication including means forimplementing any of aspects 1 to 13.

Aspect 16 is a non-transitory computer-readable storage medium storingcomputer executable code, where the code, when executed, causes aprocessor to implement any of aspects 1 to 13.

Aspect 17 is an apparatus for wireless communication, with a firstwireless device, at a second wireless device including at least oneprocessor coupled to a memory, the memory and the at least one processorconfigured to transmit, to the first wireless device, first informationat a first symbol of a first slot, the first slot including at least thefirst symbol and a first reference signal; and transmit secondinformation at a second symbol of a second slot, the second slotincluding at least the second symbol and a second reference signal, thefirst information and the second information being repetitions.

Aspect 18 is the apparatus of aspect 17, further including that thefirst slot and the second slot are separated by a threshold quantity ofslots.

Aspect 19 is the apparatus of any of aspects 17 and 18, furtherincluding that the first symbol of the first slot is associated with afirst CPE, the second symbol of the second slot is associated with asecond CPE, and a difference between the first CPE and the second CPE isless than a threshold.

Aspect 20 is the apparatus of any of aspects 17 to 18, further includingthat the first slot and the second slot are non-consecutive slots.

Aspect 21 is the apparatus of any of aspects 17 to 18, further includingthat the first slot and the second slot are consecutive slots.

Aspect 22 is the apparatus of any of aspects 17 to 21, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes an automatic gain controlsymbol, and the second information is a copy of the first information.

Aspect 23 is the apparatus of any of aspects 17 to 21, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the second information is a copy of the firstinformation, the second information including a data portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 24 is the apparatus of any of aspects 17 to 21, further includingthat the first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the first information is a copy of the secondinformation, the second information including a control portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 25 is the apparatus of any of aspects 17 to 21, further includingthat the first symbol of the first slot includes a guard symbol, thesecond symbol of the second slot includes a first non-automatic gaincontrol symbol, and the first information is a copy of the secondinformation, the second information including a control portion of thesecond symbol and the first information including a portion of the firstsymbol.

Aspect 26 is the apparatus of any of aspects 17 to 25, further includingthat the memory and the at least one processor are further configuredto: transmit a configuration indicating the first symbol and the secondsymbol.

Aspect 27 is the apparatus of any of aspects 17 to 26, further includingthat the first wireless device comprises a base station and the secondwireless device comprises a user equipment, or the first wireless devicecomprises the user equipment and the second wireless device comprisesthe base station.

Aspect 28 is the apparatus of any of aspects 17 to 26, further includingthat the first wireless device comprises a first sidelink device and thesecond wireless device comprises a second sidelink device.

Aspect 29 is the apparatus of any of aspects 17 to 28, further includinga transceiver coupled to the at least one processor.

Aspect 30 is a method of wireless communication for implementing any ofaspects 17 to 29.

Aspect 31 is an apparatus for wireless communication including means forimplementing any of aspects 17 to 29.

Aspect 32 is a non-transitory computer-readable storage medium storingcomputer executable code, where the code, when executed, causes aprocessor to implement any of aspects 17 to 29.

What is claimed is:
 1. An apparatus for wireless communication at afirst wireless device, comprising: a memory; and at least one processorcoupled to the memory, the at least one processor configured to:receive, from a second wireless device, first information at a firstsymbol of a first slot, the first slot including at least the firstsymbol and a first reference signal; receive second information at asecond symbol of a second slot, the second slot including at least thesecond symbol and a second reference signal, the first information andthe second information being repetitions; generate a first referencesignal copy based at least on the second reference signal and a phasejump between the first slot and the second slot, the phase jump based ona first phase error associated with the first symbol and a second phaseerror associated with the second symbol; and perform channel estimationacross the first slot and the second slot based on an aggregation of thefirst reference signal and the first reference signal copy.
 2. Theapparatus of claim 1, wherein the first slot and the second slot areseparated by a threshold quantity of slots.
 3. The apparatus of claim 2,wherein the first slot and the second slot are non-consecutive slots. 4.The apparatus of claim 2, wherein the first slot and the second slot areconsecutive slots.
 5. The apparatus of claim 2, wherein the phase jumpis based on a difference between the second phase error and the firstphase error.
 6. The apparatus of claim 1, wherein the first symbol ofthe first slot includes a last data symbol, the second symbol of thesecond slot includes an automatic gain control symbol, and the secondinformation is a copy of the first information.
 7. The apparatus ofclaim 1, wherein the first symbol of the first slot includes a last datasymbol, the second symbol of the second slot includes a firstnon-automatic gain control symbol, and the second information is a copyof the first information, the second information including a dataportion of the second symbol and the first information including aportion of the first symbol.
 8. The apparatus of claim 1, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes a first non-automatic gain controlsymbol, and the first information is a copy of the second information,the second information including a control portion of the second symboland the first information including a portion of the first symbol. 9.The apparatus of claim 1, wherein the first symbol of the first slotincludes a guard symbol, the second symbol of the second slot includes afirst non-automatic gain control symbol, and the first information is acopy of the second information, the second information including acontrol portion of the second symbol and the first information includinga portion of the first symbol.
 10. The apparatus of claim 1, wherein thefirst wireless device comprises a base station and the second wirelessdevice comprises a user equipment, or the first wireless devicecomprises the user equipment and the second wireless device comprisesthe base station.
 11. The apparatus of claim 1, wherein the firstwireless device comprises a first sidelink device and the secondwireless device comprises a second sidelink device.
 12. The apparatus ofclaim 1, further comprising a transceiver coupled to the at least oneprocessor.
 13. A method of wireless communication at a first wirelessdevice, comprising: receiving, from a second wireless device, firstinformation at a first symbol of a first slot, the first slot includingat least the first symbol and a first reference signal; receiving secondinformation at a second symbol of a second slot, the second slotincluding at least the second symbol and a second reference signal, thefirst information and the second information being repetitions;estimating a phase jump between the first slot and the second slot, thephase jump based on a first phase error associated with the first symboland a second phase error associated with the second symbol; andperforming channel estimation across the first slot and the second slotbased in part on the phase jump.
 14. The method of claim 13, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes an automatic gain control symbol, andthe second information is a copy of the first information.
 15. Themethod of claim 13, wherein the first symbol of the first slot includesa last data symbol, the second symbol of the second slot includes afirst non-automatic gain control symbol, and the second information is acopy of the first information, the second information including a dataportion of the second symbol and the first information including aportion of the first symbol.
 16. The method of claim 13, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes a first non-automatic gain controlsymbol, and the first information is a copy of the second information,the second information including a control portion of the second symboland the first information including a portion of the first symbol. 17.The method of claim 13, wherein the first symbol of the first slotincludes a guard symbol, the second symbol of the second slot includes afirst non-automatic gain control symbol, and the first information is acopy of the second information, the second information including acontrol portion of the second symbol and the first information includinga portion of the first symbol.
 18. The method of claim 13, furthercomprising: generating a first reference signal copy based at least onthe second reference signal and the phase jump; and performing thechannel estimation across the first slot and the second slot based on anaggregation of the first reference signal and the first reference signalcopy.
 19. An apparatus for wireless communication at a first wirelessdevice, comprising: a memory; and at least one processor coupled to thememory, the at least one processor configured to: receive, from a secondwireless device, first information at a first symbol of a first slot,the first slot including at least the first symbol and a first referencesignal; receive second information at a second symbol of a second slot,the second slot including at least the second symbol and a secondreference signal, the first information and the second information beingrepetitions; estimate a phase jump between the first slot and the secondslot, the phase jump based on a first phase error associated with thefirst symbol and a second phase error associated with the second symbol;and perform channel estimation across the first slot and the second slotbased in part on the phase jump.
 20. The apparatus of claim 19, whereinthe first symbol of the first slot includes a last data symbol, thesecond symbol of the second slot includes an automatic gain controlsymbol, and the second information is a copy of the first information.21. The apparatus of claim 19, wherein the first symbol of the firstslot includes a last data symbol, the second symbol of the second slotincludes a first non-automatic gain control symbol, and the secondinformation is a copy of the first information, the second informationincluding a data portion of the second symbol and the first informationincluding a portion of the first symbol.
 22. The apparatus of claim 19,wherein the first symbol of the first slot includes a last data symbol,the second symbol of the second slot includes a first non-automatic gaincontrol symbol, and the first information is a copy of the secondinformation, the second information including a control portion of thesecond symbol and the first information including a portion of the firstsymbol.
 23. The apparatus of claim 19, wherein the first symbol of thefirst slot includes a guard symbol, the second symbol of the second slotincludes a first non-automatic gain control symbol, and the firstinformation is a copy of the second information, the second informationincluding a control portion of the second symbol and the firstinformation including a portion of the first symbol.
 24. The apparatusof claim 19, wherein the at least one processor is further configuredto: generate a first reference signal copy based at least on the secondreference signal and the phase jump; and perform the channel estimationacross the first slot and the second slot based on an aggregation of thefirst reference signal and the first reference signal copy.
 25. Anon-transitory computer-readable storage medium comprisingcomputer-executable code at a first wireless device, thecomputer-executable code, when executed, causes a processor to: receive,from a second wireless device, first information at a first symbol of afirst slot, the first slot including at least the first symbol and afirst reference signal; receive second information at a second symbol ofa second slot, the second slot including at least the second symbol anda second reference signal, the first information and the secondinformation being repetitions; estimate a phase jump between the firstslot and the second slot, the phase jump based on a first phase errorassociated with the first symbol and a second phase error associatedwith the second symbol; and perform channel estimation across the firstslot and the second slot based in part on the phase jump.
 26. Thenon-transitory computer-readable storage medium of claim 25, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes an automatic gain control symbol, andthe second information is a copy of the first information.
 27. Thenon-transitory computer-readable storage medium of claim 25, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes a first non-automatic gain controlsymbol, and the second information is a copy of the first information,the second information including a data portion of the second symbol andthe first information including a portion of the first symbol.
 28. Thenon-transitory computer-readable storage medium of claim 25, wherein thefirst symbol of the first slot includes a last data symbol, the secondsymbol of the second slot includes a first non-automatic gain controlsymbol, and the first information is a copy of the second information,the second information including a control portion of the second symboland the first information including a portion of the first symbol. 29.The non-transitory computer-readable storage medium of claim 25, whereinthe first symbol of the first slot includes a guard symbol, the secondsymbol of the second slot includes a first non-automatic gain controlsymbol, and the first information is a copy of the second information,the second information including a control portion of the second symboland the first information including a portion of the first symbol. 30.The non-transitory computer-readable storage medium of claim 25, thecomputer-executable code, when executed, further causes the processorto: generate a first reference signal copy based at least on the secondreference signal and the phase jump; and perform the channel estimationacross the first slot and the second slot based on an aggregation of thefirst reference signal and the first reference signal copy.